SNP Heuristics - how to use "Lot Size Strategy"

Hello experts,

we are using an SNP heuristic (Plng book in weekly buckets) to calculate PReqs from an external suppliers. Right now we apply a periodic lot size of period type = M and number of periods = 1 which results in 1 monthly aggregated PReq. This works okay but we want to place the PReq always at the beginnning or end of the month and not directly at the place where the first undercoverage appears. Therefore we tested the so called "Lot Size Strategy" (APO Material master Tab "Lot Size" --> "Procedure) with values 1 and 2 but with no satisfacory result and even strange behaviour that SNP starts creating weekly PReqs again instead of monthly.

Can somebody help with this - we would like to understand how we can make use of the "Lot Size Strategy" and of the other switch called "Start of Lot Size Grouping". In addition - how does the period factor overlay this control - we are using a Period factor = 0,01 which means the PReq is being placed at a Monday of the weekly buckets.

Regards

Thomas Schulze