diff --git a/pyfstat/core.py b/pyfstat/core.py
index 3ed1e92d31ce610221e228f1f8ca87981b43de8a..2e627b93349e3f289c2175a549d313013be2eec2 100755
--- a/pyfstat/core.py
+++ b/pyfstat/core.py
@@ -554,10 +554,9 @@ class ComputeFstat(BaseSearchClass):
 
         logging.info("Initialising FstatInput")
         dFreq = 0
+        self.whatToCompute = lalpulsar.FSTATQ_2F
         if self.transientWindowType or self.computeAtoms:
-            self.whatToCompute = lalpulsar.FSTATQ_ATOMS_PER_DET
-        else:
-            self.whatToCompute = lalpulsar.FSTATQ_2F
+            self.whatToCompute += lalpulsar.FSTATQ_ATOMS_PER_DET
 
         FstatOAs = lalpulsar.FstatOptionalArgs()
         FstatOAs.randSeed = lalpulsar.FstatOptionalArgsDefaults.randSeed