fix the output issue with manual grouping

Author: Kvieta1990

total_scattering/reduction/total_scattering_reduction.py

@@ -2267,7 +2267,7 @@ def out_bragg(form, out_wksp, manual_grouping=False):
                 final_difc = [final_difc]
 
         for i in range(mtd["bo_dummy"].getNumberHistograms()):
-            if final_difc is not None:
+            if final_difc is not None and not manual_grouping:
                 difc_val = final_difc[i]
             else:
                 difc_val = mtd["calib_table_init"].row(i)["DIFC"]