I think there is likely to be very considerable scope:
1) Revenue accept that the 150% lump sum is worth much less than the 16.67% of final salary in ongoing pension foregone.
2) Spouse is only paid at 50% of pension on death of pensioner whereas Revenue permit 100%. You can fund for the shortfall.
3) If the scheme is integrated (i.e. the pensioner will receive his/her contributory OAP as part of - but not in addition to - their occupational pension) the value of the OACP can be seperately funded by means of AVCs.
Most public servants would be unable to afford the level of contributions to provide for all the above. So there is almost unlimited scope for you to make AVCs (subject to annual %age limits on contribution).
You can worry about how the AVCs get used at retirement - even if it's early.
You can't fund in excess of revenue maximum contributions to target a revenue maximum pension at 65.
So, you can't fund for Revenue max early retirement at 56 if it is a higher contribution rate than that required to target Revmax at 65...but then again Cornmarket may not be overly stringent about this, I really do not know.