Dash,
AFPS 75 allows a maximum reckonable service for pension purposes of 34 yrs for officers and 37 yrs for ORs, which with a Normal Pension Age of 55 means that pensionable service for offrs starts at 21. All the Scheme's benefits (and costs) are broadly based around those parameters, so any reduction in the age for some would reduce the benefits for all. While this may have suited the employment market and Service needs of the mid-70s (most graduates would have started from age 21) the unfairness was addressed, in part, in AFPS 05 which increased the maximum reckonable service to 40 yrs for all. As you mention you accepted the AFPS 75 terms on initial entry and you would have had the option to transfer to AFPS 05 in 2006 and have those 'missing years' counted. The next change will be following Lord Hutton's recommendation that the cap on pension accrual (i.e. maximum reckonable service for pension purposes) be removed or significantly lifted for all public sector pensions, as well as pension abatement, to fit in with the drive for greater employment flexibility and longer careers. I guess these will be factors in the new scheme.