To add to this thread, please consider adding a summary column functionality for grand total amounts for budget tables. For example: in addition to the grand total for grant requests, we need grand totals for cost shares which is a combined subtotals of in-kind cost share and third party cash cost share. Hence the need for grand total cost share of both in-kind and third party cash.
Hope this makes sense and let me know if you need clarifications.
Thank you for considering.

It would be nice to be able to show the difference between to sum lines. For example: the difference between income and expenses.

This would be a huge help for our grant application tables that currently require applicants to sum the rows manually and ultimate leads to errors on calculations. Sum would be our biggest need but have the average, subtraction, count, etc. could all be useful if available.

I'm thinking Sum, average, count might be useful...

Sum and average functions would be great on our end!

More complicated, but having the ability to add a simple formula (e.g., X/the sum to calculate a percentage or something like that) would be extremely helpful for our purposes as well.

One that could be a "nice to have" would be a subtract formula where the sum of rows 2 through x would be subtracted from the amount entered by the applicant in row 1.

Could be helpful in calculating the requested amount to the Funder for a project based on the total cost of the project minus resources already secured by the organization.

"sum" is the main feature that would be needed, at least from my perspective

I can see innumerable use cases for having an average function!