I think yellow is the test colour and red the problem colour... In the U.S. manual this button does not seem to exist...

It seems that once you have nitrogen gas you can only top up with nitrogen you can't mix with air... Normally I would check the pressure at the gas station but since they only have air, It might accidently pump some air into the tyre...

The tyre shop asked me if I wanted the nitrogen for free since I bought 4 new tyres and thought initially I would have been silly to refuse, but with top ups at 3 euros I'm thinking it's probably a good money spinner for them...

Apparently the Nitrogen is better in hot climates as it keeps the tyre cool and apparently makes the ride smoother, I can't complain the tyres feel great, but I think I should have reset the Run flat system after they were fitted...