You're right of course, none of us know the details but....
I joined at age 27, have done 16 years, do aim to serve to 55 at which point the 05 pension gives better return than the 75 hence my opting to change to 05. Sadly I'm not PAS.
I assume (yes, I know...) that as I will not serve to 55 on the 05 pension (because of it's replacement) I wont see the benifits of that scheme, and will be worse off than if I'd stayed on the 75 scheme.
I hope I've got this wrong....