Ch 7 and 8...why not able to assign some flight modes here

For example, in flight modes 1-6, I can select “drift”, but can’t assign that to ch 7 or 8. Is there a specific reason for that, or has someone simply not yet written code for that? Way beyond my abilities, but if it is just a matter of someone writing code, how do I make such a recommendation…and to whom?

Thanks.

for example, in flight modes 1-6, I can select “drift”, but can’t assign that to ch 7 or 8
Is there a specific reason for that,

Yes the flight modes are set with Channel 5. If we had a some flight modes on CH5 and some on CH7 how would we know which one to pick?