Ion programs compiled by Axe would use 83+ bcalls, addressing would start at $9D95. 83 programs are run from $9327, i think, though it's been a long time since i've done anything 83-specific, especially after Ion. Really, probably since AsmGuru! But i'm pretty sure that's right. It might be possible for Axe to spit out an 83 version, though, as long as the program doesn't use anything specific to the 83+ (and up).