I asked the same question as I am about 50 days into the high rate under the old system but seemed to indicate that I would drop to level 2 on the new. The advice I was given is that you will stay on the same level financially i.e. high = level 3 pay but you will need to accrue the correct number of days in total to step up to level 4. Effectively this means a longer period at level 3, but it seems fair in the long run.
What does amaze me is that it wasn't made clear from the outset given the furore likely by personnel thinking they were about to take a drop!
The top levels seem quite attractive pay-wise but it'll take a hell of a lot of time deployed to get there!
SBG