Fuel planning, additional optional fuel entries

Would it be possible to add even more flexibility in how we use the different fuel planning entry fields? For example, it currently does not seem to be possible to plan both APU fuel and EXTRA fuel (e.g., B737 ETOPS leg) or both ADDNL and EXTRA (e.g., 15-minute additional in lieu of alternate plus extra) on the same flight plan.

Maybe one solution would be to add selector boxes for the fields that are currently MEL, ATC, WXX, and Tankering, so we get five configurable entries rather than just one?