Can budget and forecasts be based on workplan structure instead of financial structure

We have peculiar business requirement to have simple Financial Breakdown Structure but complex Workplan Structure.  

And wants to do the budgeting and forecasting based on workplan structure and regular cost collection on FBS.

Business is fine with not copying actual cost collection on forecasts.

Basically the quesition is can the Budgets / Forecasts in project management be based on Workplan structures instead of Financial Structures?

Regards,

Nilesh