Microsoft Dynamics 365
We have made a function for this - Term Incoicing Templates. Based on the contract price - make payment plan. Also Important input to the cashflow feature that can "catch" the planninglines (with the planned dates for payment)...
Should absolutely be a part of the standard.
A lot of customers and, probably more importantly, prospects who run jobs over a long period of time use this type of billing. This would be a good addition to the Jobs module and answer a lot of questions.