After some testing i found out how it works
the “Armor/Attack Type” adds 256 x the number u type in it to the total “quantity” for the unit atk value, it’s because the variable that handles the “quantity” is of a type that can’t handle numbers bigger than 255, so they made this way around it so you can set the atk to numbers bigger than 255. If you want a number bellow than 255 just put a 0 in “Armor/Attack Type” (and yes, it ended up being a super misleading name)
For example, if you want to set the atk to 266, just put quantity to 10 and armor/atk type to 1, if you want 522 put quantity to 10 and armor/atk type to 2.
Btw trying to put a number bigger than 255 in quantity will give u a different number, and it’ll be reset when u finish testing (just set quantity to 265 and armor/atk type to 0, when i tested it gave me the number 9, after quitting i looked at the trigger and there was a 9 in the quantity field instead of 265)