The reason everything everywhere in this extensions states its supported in 5E is because that is all it IS supported in. Granted in my younger naïve days when I thought all rulesets respected the CoreRPG to give a common thread across all rulesets - I thought it could easily be supported. Unfortunately, that was naïve as all of the rulesets pretty much go off in their own direction without a care for keeping any commonality between rulesets. The extension still has some of those other rulesets listed due to this legacy of naivete, but in every post statement and everything else you can find you will see I only play 5E so I only support 5E. I do guard things in the code to be 5E only because of this foolish legacy - but that is no guarantee - as you've seen - that some ruleset won't still diverge even further to break things.
Recently I even had to remove something similar to what you say should be added because it broke 5E compatible stuff. So if you wish to modify map parcel for your own uses in pf2 - feel free. But I will not be chasing that boondoggle and trying to keep up with changes in something I do not support and do not use. Especially, if the change is not understood - as clearly the one you are asking for is not.
Still, no issue for you to change that and modify things so they work in your world. Which for now, given the nebulous change your asking for - is what you will have to do.
Keep in mind tabs are very finicky and if you don't play nice with them they will be rendered incompatible with anyone else. NEVER hardcode any tab number for sure. That goes for rulesets and extensions.
Here is what I see in PFRPG2... nothing explodes and I have no idea if that is right or wrong - but that's all I do to support that unsupported stuff - make sure it does not explode.
Attachment 56192
And if that is not what your seeing - you have extension compatibility issues. I keep my stuff as generically compatible as possible - but as per warnings in page 1 and everywhere else - conflicts happen. EXTENSIONS = RISK. And this is only supported in 5E. I've debated ripping out all that legacy stuff that lets people put it in other rulesets - but I figure leave it in case they want to do their own things.

