Yeah this is a good idea and it goes beyond just Accounting.
I did some thinking a while back about a “Metrics” DocType that might dovetail with Dashboards/Charts and allow the creation of equations and functions that would allow for tracking OKR/KPI type stuff.
This would allow for things like LTV, Churn, Open Rates, Conversion Rates etc.
I found my last sketch of the idea and include it here: