Sounds like you hit the 6500 'limiter' built in by Nissan for your car. However, the red light comes on at whatever 'limit' you choose to dial in on the 'up-shift indicator' - you could set it as low as 2000rpm if you wanted but it will not affect the car's built in limiter.
I have my red light set at 6500rpm which is 100rpm below Nissan's recommended change up for my 2006 ZED, so as to get the best torque (grunt!) from the engine although the built in limiter dosen't kick in until 7000rpm. You have probably noticed the light flashes before it is constant at the dialled in limit, which I personally find more eye-catching to help warn of a change up when the engine note is being drowned by other noise (Usually Mrs E shouting at me to slow down ).
I did make a lot of use of the change-up light in my current ZED (bought new), gradually increasing the limit from under the 4000rpm Nissan say for the running-in period, and then upwards in incremental periods afterwards. Many say running-in is not necessary and they may well be right, but I would rather not put undue strain on a new engine unnecessarily in the early part of its life, as well as other components in the car such as the gearbox and brakes. I my present ZED and may well keep it more than the 3 years I normally keep a car hence I have been particular about its early life.
To be honest, the light is bit of a gimmick but you will have seen most racing cars use them these days and I guess Nissan saw the car being used on the track where the light's worth is greater . That is something I plan to test in due course.....