As @borisphotosafari mentioned, Thresher Shark Divers separates the people on a boat into air and Nitrox divers. So everyone in your group will be Nitrox divers, if you choose Nitrox. So the air divers having a shorter NDL won't be an issue.
If you run out of air before you reach your NDL limit then Nitrox isn't going to help you. For example, I believe, at 60 feet the NDL on air is 55 minutes and on EAN32 it is 90 minutes. But if you can only last 40 minutes on a tank then EAN32 isn't going to help. If you are finishing a dive with plenty of air and your computer is saying you are reach NDL, then Nitrox will help increase your bottom time.
There is a third reason to use Nitrox. I was diving 3 or 4 times a day for 12 days. In theory, I should be fine diving all the time on air BUT it doesn't hurt to reduce the amount of nitrogen you are exposed to. Using EAN32 meant I was exposing myself to 68% nitrogen on each dive rather than 79% nitrogen. In theory this reduces your risk for DCS. There are many factors which increase your chance of DCS. The more you reduce those factors the less likely you are to get bent. Using Nitrox reduces one of the many factors.
Bottom line, I used Nitrox when I went diving at Malapascua Island.
If you run out of air before you reach your NDL limit then Nitrox isn't going to help you. For example, I believe, at 60 feet the NDL on air is 55 minutes and on EAN32 it is 90 minutes. But if you can only last 40 minutes on a tank then EAN32 isn't going to help. If you are finishing a dive with plenty of air and your computer is saying you are reach NDL, then Nitrox will help increase your bottom time.
There is a third reason to use Nitrox. I was diving 3 or 4 times a day for 12 days. In theory, I should be fine diving all the time on air BUT it doesn't hurt to reduce the amount of nitrogen you are exposed to. Using EAN32 meant I was exposing myself to 68% nitrogen on each dive rather than 79% nitrogen. In theory this reduces your risk for DCS. There are many factors which increase your chance of DCS. The more you reduce those factors the less likely you are to get bent. Using Nitrox reduces one of the many factors.
Bottom line, I used Nitrox when I went diving at Malapascua Island.
