Expansion of Treasure Chest subroutine

I still don't understand why DEC $1C seems to be a 16-bit operation but INC $24 is only a 8-bit one. Does JSR has something to do with it?

what makes you think this?  i never see your code change register size mid-function.  so i think it's all 16-bits.

Nevermind, I messed up the endianness in my head so I uselessly added operations to put $25 into $24 later in the code... and I just forgot about it a week later!

I applied your suggestions. They work perfectly and the code is now 24 bytes smaller!