I originally posted about most people topping out at MX11A - I think your estimate isn't too far off. To the previous poster who mentioned greater aspirations, one has to bear in mind that there are more graduates than before, and hence more MXes entering the system.

Capping people at MX11A helps to control manpower costs, but it's not great for morale when you see unexperienced scholarship holders being pushed up to MX10 DD level (plus they have additional PSLP allowances on top of the basic MX11A salary) in their early 30s (though the question of course would be whether anyone really cares about the morale of the non-scholarship holders in the first place).