diff --git a/numass-core/src/main/java/inr/numass/data/analyzers/AbstractAnalyzer.java b/numass-core/src/main/java/inr/numass/data/analyzers/AbstractAnalyzer.java
index 25d4cded..88b9ab9c 100644
--- a/numass-core/src/main/java/inr/numass/data/analyzers/AbstractAnalyzer.java
+++ b/numass-core/src/main/java/inr/numass/data/analyzers/AbstractAnalyzer.java
@@ -8,6 +8,7 @@ import hep.dataforge.tables.TableFormatBuilder;
 import inr.numass.data.api.*;
 import org.jetbrains.annotations.Nullable;
 
+import java.util.Comparator;
 import java.util.stream.Stream;
 
 import static hep.dataforge.tables.XYAdapter.*;
@@ -44,7 +45,12 @@ public abstract class AbstractAnalyzer implements NumassAnalyzer {
         } else if (getProcessor() == null) {
             throw new IllegalArgumentException("Signal processor needed to analyze frames");
         } else {
-            return Stream.concat(block.getEvents(), block.getFrames().flatMap(getProcessor()::analyze));
+            //TODO
+            Stream<NumassEvent> res = Stream.concat(block.getEvents(), block.getFrames().flatMap(getProcessor()::analyze));
+            if (config.getBoolean("sort", false)) {
+                res = res.sorted(Comparator.comparing(NumassEvent::getTimeOffset));
+            }
+            return res;
         }
     }
 
diff --git a/numass-core/src/main/java/inr/numass/data/analyzers/TimeAnalyzer.java b/numass-core/src/main/java/inr/numass/data/analyzers/TimeAnalyzer.java
index 96d70af2..44fb8a87 100644
--- a/numass-core/src/main/java/inr/numass/data/analyzers/TimeAnalyzer.java
+++ b/numass-core/src/main/java/inr/numass/data/analyzers/TimeAnalyzer.java
@@ -90,9 +90,6 @@ public class TimeAnalyzer extends AbstractAnalyzer {
         AtomicReference<NumassEvent> lastEvent = new AtomicReference<>(null);
 
         Stream<NumassEvent> eventStream = super.getEvents(block, config);//using super implementation
-        if (config.getBoolean("sort", false)) {
-            eventStream = eventStream.sorted();
-        }
 
         return eventStream.map(event -> {
             if (lastEvent.get() == null) {
diff --git a/numass-core/src/main/java/inr/numass/data/api/MetaBlock.java b/numass-core/src/main/java/inr/numass/data/api/MetaBlock.java
index 33a785cb..1c809246 100644
--- a/numass-core/src/main/java/inr/numass/data/api/MetaBlock.java
+++ b/numass-core/src/main/java/inr/numass/data/api/MetaBlock.java
@@ -32,11 +32,15 @@ public class MetaBlock implements NumassBlock {
 
     @Override
     public Stream<NumassEvent> getEvents() {
-        return blocks.stream().flatMap(NumassBlock::getEvents).sorted(Comparator.comparing(NumassEvent::getTime));
+        return blocks.stream()
+                .sorted(Comparator.comparing(NumassBlock::getStartTime))
+                .flatMap(NumassBlock::getEvents);
     }
 
     @Override
     public Stream<NumassFrame> getFrames() {
-        return blocks.stream().flatMap(NumassBlock::getFrames).sorted(Comparator.comparing(NumassFrame::getTime));
+        return blocks.stream()
+                .sorted(Comparator.comparing(NumassBlock::getStartTime))
+                .flatMap(NumassBlock::getFrames);
     }
 }
diff --git a/numass-core/src/main/java/inr/numass/data/api/NumassEvent.java b/numass-core/src/main/java/inr/numass/data/api/NumassEvent.java
index 573cec14..eb48edcf 100644
--- a/numass-core/src/main/java/inr/numass/data/api/NumassEvent.java
+++ b/numass-core/src/main/java/inr/numass/data/api/NumassEvent.java
@@ -15,8 +15,6 @@
  */
 package inr.numass.data.api;
 
-import org.jetbrains.annotations.NotNull;
-
 import java.io.Serializable;
 import java.time.Instant;
 
@@ -25,7 +23,7 @@ import java.time.Instant;
  *
  * @author Darksnake
  */
-public class NumassEvent implements Comparable<NumassEvent>, Serializable {
+public class NumassEvent implements Serializable {
     // channel
     private final short chanel;
     //The time of the block start
@@ -65,9 +63,4 @@ public class NumassEvent implements Comparable<NumassEvent>, Serializable {
     public Instant getTime() {
         return blockTime.plusNanos(timeOffset);
     }
-
-    @Override
-    public int compareTo(@NotNull NumassEvent o) {
-        return this.getTime().compareTo(o.getTime());
-    }
 }
diff --git a/numass-core/src/main/java/inr/numass/data/api/SimpleNumassPoint.java b/numass-core/src/main/java/inr/numass/data/api/SimpleNumassPoint.java
index 7269617d..b0dfac77 100644
--- a/numass-core/src/main/java/inr/numass/data/api/SimpleNumassPoint.java
+++ b/numass-core/src/main/java/inr/numass/data/api/SimpleNumassPoint.java
@@ -4,6 +4,7 @@ import hep.dataforge.meta.Meta;
 import hep.dataforge.meta.MetaBuilder;
 import hep.dataforge.utils.MetaHolder;
 
+import java.util.Comparator;
 import java.util.List;
 import java.util.stream.Stream;
 
@@ -21,11 +22,13 @@ public class SimpleNumassPoint extends MetaHolder implements NumassPoint {
      */
     public SimpleNumassPoint(double voltage, List<NumassBlock> blocks) {
         this.blocks = blocks;
+        blocks.sort(Comparator.comparing(NumassBlock::getStartTime));
         super.setMeta(new MetaBuilder("point").setValue(HV_KEY, voltage));
     }
 
     public SimpleNumassPoint(Meta meta, List<NumassBlock> blocks) {
         super(meta);
+        blocks.sort(Comparator.comparing(NumassBlock::getStartTime));
         this.blocks = blocks;
     }
 
diff --git a/numass-core/src/main/java/inr/numass/data/storage/NumassDataLoader.java b/numass-core/src/main/java/inr/numass/data/storage/NumassDataLoader.java
index 4b848d4d..7f4f7832 100644
--- a/numass-core/src/main/java/inr/numass/data/storage/NumassDataLoader.java
+++ b/numass-core/src/main/java/inr/numass/data/storage/NumassDataLoader.java
@@ -28,6 +28,7 @@ import hep.dataforge.storage.filestorage.FileEnvelope;
 import hep.dataforge.storage.filestorage.FileStorage;
 import hep.dataforge.storage.loaders.AbstractLoader;
 import hep.dataforge.tables.Table;
+import hep.dataforge.values.Value;
 import inr.numass.data.api.NumassPoint;
 import inr.numass.data.api.NumassSet;
 import org.slf4j.LoggerFactory;
@@ -221,11 +222,7 @@ public class NumassDataLoader extends AbstractLoader implements ObjectLoader<Env
 
     @Override
     public Instant getStartTime() {
-        if (meta().hasValue("start_time")) {
-            return meta().getValue("start_time").timeValue();
-        } else {
-            return NumassSet.super.getStartTime();
-        }
+        return meta.optValue("start_time").map(Value::timeValue).orElseGet(()->NumassSet.super.getStartTime());
     }
 
     @Override
diff --git a/numass-core/src/main/java/inr/numass/data/storage/ProtoNumassPoint.java b/numass-core/src/main/java/inr/numass/data/storage/ProtoNumassPoint.java
index 5b968e27..e5a8f8fb 100644
--- a/numass-core/src/main/java/inr/numass/data/storage/ProtoNumassPoint.java
+++ b/numass-core/src/main/java/inr/numass/data/storage/ProtoNumassPoint.java
@@ -15,6 +15,7 @@ import java.nio.ByteBuffer;
 import java.nio.file.Path;
 import java.time.Duration;
 import java.time.Instant;
+import java.util.Comparator;
 import java.util.stream.IntStream;
 import java.util.stream.Stream;
 
@@ -44,9 +45,12 @@ public class ProtoNumassPoint implements NumassPoint {
 
     @Override
     public Stream<NumassBlock> getBlocks() {
-        return getPoint().getChannelsList().stream().flatMap(channel ->
-                channel.getBlocksList().stream().map(block -> new ProtoBlock((int) channel.getNum(), block))
-        );
+        return getPoint().getChannelsList().stream()
+                .flatMap(channel ->
+                        channel.getBlocksList().stream()
+                                .map(block -> new ProtoBlock((int) channel.getNum(), block))
+                                .sorted(Comparator.comparing(ProtoBlock::getStartTime))
+                );
     }
 
     @Override
diff --git a/numass-main/build.gradle b/numass-main/build.gradle
index 137f7c41..baaac5a0 100644
--- a/numass-main/build.gradle
+++ b/numass-main/build.gradle
@@ -58,6 +58,6 @@ task simulate(dependsOn: classes, type: JavaExec) {
 
 task underflow(dependsOn: classes, type: JavaExec) {
     group "numass"
-    main 'inr.numass.scripts.Underflow'
+    main 'inr.numass.scripts.underflow.Underflow'
     classpath = sourceSets.main.runtimeClasspath
 }
\ No newline at end of file
diff --git a/numass-main/src/main/groovy/inr/numass/scripts/underflow/Underflow.groovy b/numass-main/src/main/groovy/inr/numass/scripts/underflow/Underflow.groovy
index 6236d855..57c44dd6 100644
--- a/numass-main/src/main/groovy/inr/numass/scripts/underflow/Underflow.groovy
+++ b/numass-main/src/main/groovy/inr/numass/scripts/underflow/Underflow.groovy
@@ -46,7 +46,7 @@ ctx.pluginManager().load(CachePlugin.class)
 
 Meta meta = buildMeta {
     data(dir: "D:\\Work\\Numass\\data\\2017_05\\Fill_2", mask: "set_.{1,3}")
-    generate(t0: 3e4, sort: true)
+    generate(t0: 3e4, sort: false)
     subtract(reference: 18600)
     fit(xlow: 450, xHigh: 700, upper: 3100, binning: 20)
 }
@@ -76,13 +76,13 @@ new GrindShell(ctx).eval {
     def dataBuilder = DataSet.builder(NumassPoint);
 
     sets.sort { it.startTime }
-            .collectMany { it.points.collect() }
-            .groupBy { it.voltage }
-            .each { key, value ->
-                def point = new SimpleNumassPoint(key as double, value as List<NumassPoint>)
-                String name = (key as Integer).toString()
-                dataBuilder.putStatic(name, point, buildMeta(voltage: key));
-            }
+        .collectMany { it.points.collect() }
+        .groupBy { it.voltage }
+        .each { key, value ->
+        def point = new SimpleNumassPoint(key as double, value as List<NumassPoint>)
+        String name = (key as Integer).toString()
+        dataBuilder.putStatic(name, point, buildMeta(voltage: key));
+    }
 
     DataNode<NumassPoint> data = dataBuilder.build()
 
@@ -102,8 +102,8 @@ new GrindShell(ctx).eval {
         spectraMap = spectra
                 .findAll { it.name != referenceVoltage }
                 .collectEntries {
-            return [(it.meta["voltage"].doubleValue()): NumassDataUtils.subtractSpectrum(it.get(), referencePoint)]
-        }
+                    [(it.meta["voltage"].doubleValue()): NumassDataUtils.subtractSpectrum(it.get(), referencePoint)]
+                }
     } else {
         spectraMap = spectra.collectEntries { return [(it.meta["voltage"].doubleValue()): it.get()] }
     }