I suspect that you have been 'dynamised' !! ( search under BMA GP pensions).
As you have not received a pay rise for several years, your pension would be worth less than one of your colleagues who retired prior to the pay freeze, but whose pension has increased by the annual CPI rate thus disadvantaging you for the extra years you have served. In effect your frozen salary is 'dynamised' up by the CPI increases since the pay freeze and that bigger 'dynamised' salary is the basis for the calculation of your pension. The calculator is unable to show this as I believe it to be a manual calculation by the gnomes at Glasgow.
Future increases of your pension will be subject to CPI.
CNN