Combining 2 extension tables

If we have 2 extension tables and want to combine those two tables into one, what would be the best approach?

Do we add the fields of Table B to Table A and deprecate Table B as well as unmark it as an extension table?

Replacing my original comment with this one. We want to test to verify this works before we make any recommendations.

@brendan.b have you or anyone been able to perform such a test?