So if you're in to 55 when it enters, you'll still be in to 55... it's the gap to 60/SPA and what happens with the poor guys who're about to hit 38/16 points and consider longer service if a promotion is now only tied to (say) service to 44.
There would be a few long faces if grandfather rights saw you discharged 5 years short of a full pension. I would be surprised if this was applied universally as there would be little point in staying in.
Promotion to sqn ldr will equal LOS 30 (end of Tier 2); promotion to wg cdr (Tier 3) will see you to age 60. The working assumption is that PAS will also see an offer to age 60.
Aircrew officers will be exempt from the 12 year 'up-or-out' point as completion of first OCU will trigger an offer of service to the 20 year (EDP) point.
I have seen nothing on transitional arrangements beyond the rather worrying 'single-service manning control opportunities' phrase.
As accommodation and housing charges increase as you move through the Tiers it will be interesting to see how the new pay bands work.