That was what I did.
Changed in the ME, thanks for the info and the link, I think I found a bug, gonna do a few more testings just to be sure.
If I chose in the ME the ammo type as HEI and then spawn on the ground or in the air the problem occurs, the new piper is in the AP position.
If I instead chose CM in the ME, or just leave it as is the default, and then request a rearm on the ground for HEI, then change the piper it is on the right position.
Just need a few more tests when I get some free time to be sure. So far spawning with CM, rearming, then changing the IFFCC seems to work, while spawing with HEI it will always be inaccurate.