There are some people that delve fairly deeply into this game (why I will never know but different discussion there). In most discussions of the concept in other games this concept is known as level scaling by the way which could make for a better search term.
https://tvtropes.org/pmwiki/pmwiki.php/Main/LevelScaling
Two approaches you could use, maybe three.
1) Your character's level and/or experience (level in games can be an artificial thing/display only thing based on the experience counter rather than being its own thing) will have to be read as part of it, and presumably at the start of battle rather than at the end/after killing the enemy (wherever such things get applied -- if you level up in battle then the latter, if you only get it at the end screen then more likely the former). Anyway this then means
2) The enemy's HP (and other stats likely nearby) will get generated again presumably at the start of battle. Find where this is in memory (once in battle should be a fairly standard do damage, search for change, do damage, search for change... type cheat search) and note it, revert to a savestate you took before battle if you can or start a new one maybe (don't know what pointers are like in this). If you can find max HP (usually nearby in most RPGs with the other stats) then do that as well as it might save you a few steps.
In either case a break on read for the former or break on write for the latter will be involved in the chain of calculating the multiplier or using it.
The third would be if you know the location of the base stats of the game (might have to force your character to level 1 or matching the stated levels of the enemy) then that would also be involved in the calculation. Finding such a thing is doable enough in non scaled games but harder in scaled ones so whether you do (or again if someone has already done it) might vary.
