# MutantHub mutant #2927: BIP94 retarget base taken from the last block of the previous period instead of the first block of the current one
# Repository: bitcoin/bitcoin @ dc3cd1969ed35f0ca3e468fffd153e304f9f3c41
# File: src/pow.cpp:71-71
# Review: APPROVED; outcome: SURVIVED
diff --git a/src/pow.cpp b/src/pow.cpp
index 9a9f4e5..2d459a6 100644
--- a/src/pow.cpp
+++ b/src/pow.cpp
@@ -68,7 +68,7 @@ unsigned int CalculateNextWorkRequired(const CBlockIndex* pindexLast, int64_t nF
         // Here we use the first block of the difficulty period. This way
         // the real difficulty is always preserved in the first block as
         // it is not allowed to use the min-difficulty exception.
-        int nHeightFirst = pindexLast->nHeight - (params.DifficultyAdjustmentInterval()-1);
+        int nHeightFirst = pindexLast->nHeight - params.DifficultyAdjustmentInterval();
         const CBlockIndex* pindexFirst = pindexLast->GetAncestor(nHeightFirst);
         bnNew.SetCompact(pindexFirst->nBits);
     } else {