Hexadecimal code doesn't match with Invoke Battle?

I'm trying to have a specific monster appear when you kick the treasure chest in the imperial camp.
Event CB/0DFB tells me it invokes a battle with a certain enemy formation. I took the formation with the desired enemy, turned it to hexadecimal and replaced in CB/0DFB 4D 2A 02 with formation nº 43, to CB/0DFB 4D 2B 02 but instead of getting me formation 43, it gives me formation 67.

So I checked what formation 2A gives me and it turns out it's 66, not 42 which would be the decimal translation. I tried searching for 2A - 12 (hexadecimal), 14, and I get another different formation! What's going on here?

Even though the event commands list doesn't mention anything special for that commamd other than removing swoosh and transition, then a flag for battle background.

It almost sounds like its either calculating the value based off something, or its using that value to choose one of the local formations (that really doesn't sound right but).

I would try a few consecutive values, starting with the vanilla formation, write them all down and look for some sort of pattern. Then go from there.

Without a better answer, go with the most simple basic test first.

Command 4D summons a pack, not a formation. Index 0 is pack 256. So 4D 00 XX summons the lobo in Narshe school.

Oohh, of course! How did I not think of that before? xD
I actually had a feeling it might be packs instead, but my silly little mind thought "That can't be, how else would it summon a specific monster?" ...yeah I'm a dumbass. Thanks!