diff --git a/src/classes/PRunMuMinus.cpp b/src/classes/PRunMuMinus.cpp
index ca94366e..5440e154 100644
--- a/src/classes/PRunMuMinus.cpp
+++ b/src/classes/PRunMuMinus.cpp
@@ -383,7 +383,7 @@ Double_t PRunMuMinus::CalcMaxLikelihood(const std::vector<Double_t>& par)
   Int_t chunk = (fEndTimeBin - fStartTimeBin)/omp_get_num_procs();
   if (chunk < 10)
     chunk = 10;
-  #pragma omp parallel for default(shared) private(i,time,theo,data) schedule(dynamic,chunk) reduction(-:mllh)
+  #pragma omp parallel for default(shared) private(i,time,theo,data) schedule(dynamic,chunk) reduction(+:mllh)
   #endif
   for (i=fStartTimeBin; i < fEndTimeBin; ++i) {
     time = fData.GetDataTimeStart() + static_cast<Double_t>(i)*fData.GetDataTimeStep();
diff --git a/src/classes/PRunSingleHisto.cpp b/src/classes/PRunSingleHisto.cpp
index ebe601ea..1a44839c 100644
--- a/src/classes/PRunSingleHisto.cpp
+++ b/src/classes/PRunSingleHisto.cpp
@@ -439,7 +439,7 @@ Double_t PRunSingleHisto::CalcChiSquareExpected(const std::vector<Double_t>& par
  * <b>OpenMP Parallelization:</b>
  * - Dynamic scheduling with chunk size = (N_bins / N_processors), minimum 10
  * - Private variables per thread: i, time, theo, data
- * - Reduction performed on mllh sum (note: reduction(-:mllh) for subtraction)
+ * - Reduction performed on mllh sum (reduction(+:mllh))
  *
  * <b>When to Use Maximum Likelihood vs. χ²:</b>
  * - <b>Use likelihood:</b> Low count rates (< 100 counts/bin), asymmetric errors
@@ -515,7 +515,7 @@ Double_t PRunSingleHisto::CalcMaxLikelihood(const std::vector<Double_t>& par)
   Int_t chunk = (fEndTimeBin - fStartTimeBin)/omp_get_num_procs();
   if (chunk < 10)
     chunk = 10;
-  #pragma omp parallel for default(shared) private(i,time,theo,data) schedule(dynamic,chunk) reduction(-:mllh)
+  #pragma omp parallel for default(shared) private(i,time,theo,data) schedule(dynamic,chunk) reduction(+:mllh)
   #endif
   for (i=fStartTimeBin; i<fEndTimeBin; ++i) {
     time = fData.GetDataTimeStart() + static_cast<Double_t>(i)*fData.GetDataTimeStep();
@@ -650,7 +650,7 @@ Double_t PRunSingleHisto::CalcMaxLikelihoodExpected(const std::vector<Double_t>&
   Int_t chunk = (fEndTimeBin - fStartTimeBin)/omp_get_num_procs();
   if (chunk < 10)
     chunk = 10;
-  #pragma omp parallel for default(shared) private(i,time,theo,data) schedule(dynamic,chunk) reduction(-:mllh)
+  #pragma omp parallel for default(shared) private(i,time,theo,data) schedule(dynamic,chunk) reduction(+:mllh)
   #endif
   for (i=fStartTimeBin; i<fEndTimeBin; ++i) {
     time = fData.GetDataTimeStart() + static_cast<Double_t>(i)*fData.GetDataTimeStep();