If you are diving on Air, but you have told your computer that you are also carrying EAN32, the calculated TTS and (I think) the NDL will be wrong. I think you don't care about seeing your TTS, but obviously you do care about your NDL.
If the computer thinks you are carrying EAN32, then it's going to assume you are going to switch to it during your ascent. So, when it calculates what your tissue loading will be when you arrive at the surface, it's going to think you'll have less inert gas than what you really will. Thus, I think it will give you a longer NDL than it should.
If you are diving with Air and EAN32 off, and then doing a second dive with EAN32 and leaving Air turned on, I can't see a problem, off the top of my head (as far as resulting incorrect calculations), but it's still a bad habit.
Bottom line: Use your computer correctly. Don't tell it that you are carrying gases that you are not carrying. Going through the menus "the long way" to turn one gas on and another one off just isn't that time-consuming. Especially on a Teric.
If you do that, then you will have no reason to change the ppO2 limit settings.
If changing the computer "the long way" is too tedious, then just dive Nitrox all the time...