FJ2ME,
I stand to be corrected by AL R, but i believe this to be the case (yours is similar to mine).
If you leave after April 2015, due to the statement on accrued rights, you will recieve X/16ths of your pension + a lump sum of 3-times this (where X is your number of years on AFPS 75) immediately. Any benefits earnt under the new scheme will be paid from State retirement age (most likely 68 for you and I) if you don't serve until age 55. If you did make it to age 55, you would recieve these benefits at age 60. I think thats about it.