diff --git a/src/Compression/CompressionCodecFPC.cpp b/src/Compression/CompressionCodecFPC.cpp
index ec8efa0fb38..7246082caea 100644
--- a/src/Compression/CompressionCodecFPC.cpp
+++ b/src/Compression/CompressionCodecFPC.cpp
@@ -440,7 +440,7 @@ private:
         first = decompressValue(value1, is_dfcm_predictor1);
         second = decompressValue(value2, is_dfcm_predictor2);
 
-        return 1 + tail_size1 + tail_size2;
+        return expected_size;
     }
 
     static void* valueTail(TUInt& value, UInt32 compressed_size)