Diffident
I might be wrong, but we are not asked to make a choice from a neutral standpoint, per sec. We are simply invited to join the new scheme by diverting from the default path, which is AFPS75. If an individual doesn't return the acceptance letter before the deadline (which appears to moving the right) the AFPAA have the right to take the view that he is not accepting the offer and intends to remain on AFPS75. Its the same principle as binning a double glazing deal in a mailshot. Therefore, if you "elect to defer" your decision you are effectively acknowledging receipt of the offer and then turning it down. You might get a return phone call or a letter to confirm that your reply was to decline the once only offer.