diff --git a/src/delta_barth/analysis/forecast.py b/src/delta_barth/analysis/forecast.py
index 239aa64..7b9d09e 100644
--- a/src/delta_barth/analysis/forecast.py
+++ b/src/delta_barth/analysis/forecast.py
@@ -259,6 +259,12 @@ def _process_sales(
 
     min_date = dates.min()
 
+    stride = dopt_basics.datetime.timedelta_from_val(365, TimeUnitsTimedelta.DAYS)
+
+    dates = cast(pd.DatetimeIndex, monthly_sum.index)
+
+    min_date = dates.min()
+
     # print("dates: ", dates)
     # ?? --- new: use monthly basis for time windows
     # baseline: 3 years - 36 months
@@ -268,12 +274,12 @@ def _process_sales(
     #     (i for i, date in enumerate(dates) if date >= starting_date), len(dates) - 1
     # )
     # print("start idx: ", start_index, "length dates: ", len(dates))
-    # starting_date = datetime.datetime.now() - relativedelta(months=36)
-    starting_date = dates.max() - relativedelta(months=36)
-    start_index = next(
-        (i for i, date in enumerate(dates) if date >= starting_date), len(dates) - 1
-    )
-    print("start idx: ", start_index, "length dates: ", len(dates))
+    starting_date = datetime.datetime.now() - relativedelta(months=12)
+    # starting_date = dates.max() - relativedelta(months=36)
+    # start_index = next(
+    #     (i for i, date in enumerate(dates) if date >= starting_date), len(dates) - 1
+    # )
+    # print("start idx: ", start_index, "length dates: ", len(dates))
 
     def get_index_date(
         dates: pd.DatetimeIndex,