So, we have sales values that present a "perm fee" but we want to tier it out over 6 months. The challenge is integrating this into a row-based layout and taking each month's value (and somehow remembering it) as we progress down each row yet only divvying it out for 6 months. For example:

Month | Perm Fee | Payout
1 | $3000 | 500
2 | $3000 | 1000
3 | $0 | 1000
4 | $0 | 1000
5 | $3000 | 1500
6 | $0 | 1500
7 | $0 | 1000
8 | $0 | 500
9 | $0 | 500
10| $6000 | 1500

The trick is to know when the $500 (1/6 of 3k) expires from month 1. Any way to put that into a row-based formula?