FreeFlyFreak
Contributor
Out of all of them the Perdix (IMO) has the worst UI. I was also particularly infuriated (and still am) that in Rec mode (for me the best layout with all the relevant info) it has a max depth limit (default to 40m max to 50m) and artificially limits the gas MOD - so yes even Perdix has "Nanny modes"
I am not at home till Friday to check, but as I recall the max depth and gas MOD can both be changed in Rec mode. Though the settings for those are deep in the advanced section.
Try updating your firmware and digging around in settings.