I have been following the progress of VENG with some interest, although I am not entirely certain as to how attractive the package really is.
Bear with me, I may be missing something here - but say for instance that at your 22 year point you are entitled to an immediate pension, and let's just assume that the amount you will get is about £500pcm (more or less).
In real terms, the army is asking you to do the same job under the same terms and conditions of service for £500 a month less - because that's how much you would have received if you had have stayed in bed.
Now, I appreciate that the extra time you do in colour service will count towards a pension, but unless the annual increase is about £6k, then in real terms you will have lost out by staying in.
All this of course assumes that you can get a job that pays the amount you earn now (minus £500 - or whatever your pension is).
I appreciate that some soldiers would pay the army to stay in, and others may not be in the best position to leave (house prices etc), but in real terms you are on a loser with this one (purely financially speaking)