Not sure what that means but I’m not convinced it would be useful for me.
I have no intention of writing the code to support every possible users tax calculation, however entering the formula used by a few employees all with similar circumstances is not that hard particularity when the results can be easily checked against a calculator provided by the tax department.
The ability for a user to enter a formula to calculate the tax would be the most valuable feature
Batch sending emails the second most useful for me.