Difference between "premiss" and "premise"
The OED has premiss only as a variant spelling of premise, and has a note "In Logic still freq. in form premiss, but in general use now usu. in form premise. (I can't find a date on the entry, but it includes a citation from 2000) "
Premiss when taken as a logical postulate upon which a philosophical argument is founded.
Premise when a mere, as yet unfounded, presumption.
So one is a subset of the other. They may be interchangeable but not always.