Oddities can happen after editing, though the failure of the boat to clear the CO2 and refresh the O2 is usually a "shelling-out to Windows while the game is running" problem. Even if Windows does the interrupting for you, by interrupting of the game with a background process, such as the AV scanner or anything "systray" related, it can potentially mess things up. If after you surface, your O2 does not restore, then Save the game, exit the game, re-start it, and then load that Save game, and it should "fix" the issue. Note the "exit the game"... If that sequence does not re-set the CO2, then your edits might be out-of-bounds for the variable(s). The game has been known to react to such in some rather strange ways...
