I seem to recall that 29,000ft is the standard maximum altitude that the 146 with the semi-automatic pressurisation system fitted (which is what is fitted in our simulation). Certain aircraft then have a modified pressurisation system that increases their maximum altitude to 30,000ft or 31,000ft. This requires a change to the positive relief control valve's setting in the pressurisation system, which changes automatically based on the aircraft's altitude.
So I believe the correct procedure would be to select 29,000ft on the pressurisation controller, and then if the aircraft is certified for 30,000ft or 31,000ft the positive relief control valve will automatically control the pressurisation above 29,000ft.
There are then aircraft fitted with a fully automatic pressurisation system, which are cleared up to 35,000ft and that is the system we are simulating in the upcoming RJ Professional.
Mark - Just Flight