Is the Alchemist calculating proficiency with bombs correctly?

[Nyarlathotep]

Hey all,

I've been auditing an alchemist character (18th level Goblin Alchemist, 20 DEX) and I think HLO is miscalculating the proficiency bonus with bombs.

I calculate the bonus to hit with a Major Alchemist's Fire Flask as:

Proficiency Bonus: +22 (+18 for level, +4 for Alchemical Weapon Expertise gained at lvl 7)
Dex Bonus: +5
Major Flask: +3 item bonus
Total: +30

HLO is showing +32.

I suspect that it may be giving the Alchemist Master Proficiency with alchemical bombs instead of Expert (at lvl 17 Alchemical Mastery increases class DC to master proficiency but not alchemical bombs).

I can't find where HLO breaks down the to hit bonus so it's possible I'm missing something, but can anyone else confirm this?