I've noticed in PkHex that you can edit your records for the Battle Frontier for each game by going into your Trainer info, but for some reason you can't do that in Gen 5. What gives? Is it even possible to edit your record for the Battle Subway in Gen 5 to skip right away to the Subway bosses? I'd like some answers.
Thank you very much.
Basically, each generation (and sub-generation - RS vs FRLG vs E for one) is different.
PkHeX was invented as an editor for X/Y, nothing more and nothing less; and if you look at its design, it's focused on the Pokemons themselves - features like changing your position, badges, progress in story, ... have comparatively less work put behind them; then they started adding the ability to open previous generations' saves to export the Pokemon for the purpose of easy bulk transfers to gen 6, and later still the goal became becoming an unified editor for all generations...
And that means the low interest for editing things beyond Pokemon and items meets the lower interest for old games (no bonus points for the 5th generation being one of the most controversial, and in that "old but not retro" age) -- so the reason it's not implemented may very well be "those who know how to do it, haven't needed to (with PkHeX) yet"!
Early this summer I did some research on gen 3 event flags/variables, posted it to their github, and in less than 2 weeks it was kinda included.
While your example is relatively simple to find in a save (it's a visible number, make some saves with it known and not changing, make some with different values, compare them) there's a lot going on in a Pokemon game's save (checksums, encryption, sections/partitions) that makes manual comparing a big hassle: if you could create such sample saves yourself and then politely submit them to the PkHeX team, you would probably have a great chance of getting your request heard and done!