Hey Salesforce Fam,

I'm in the media business and i'm looking to realize profits off of product schedules monthly by subtracting monthly costs from the revenue schedule amount installments.

So - If I have a $120,000 deal that's paid monthly ($100,000) on my revenue schedule paid in 12 installments, i'd love to build a formula that subtracts the total cost of what I spent to service that deal in that specific product schedule month.

I know I can't add fields to Product Schedules, but what if I put a number in the comments section each month and was able to build a formula;

IF Opportunity Product Schedule Date = 7/19/2019,
THEN [Revenue] (-) [Comments]

Has anybody tried out this idea or figured another way of doing this?