SUMIF() function for Subforms and reverse reference

Dears,

It would be of great help a SUMIF feature when working with subforms and reverse references.

Sometime, you want to have aggregated data at form level, but only with specific aggregation options (maybe restrict using a date field in the subform to choose only values from a specific period or similar).

I know that something similar can be achieved with Reports, but we have the problem of not being able to export them through APIs.

What do you guys think?

Luigi