not a very scientific measurement unfortunately. I always think that when you get a reverse dilation like that it's because the head is not well applied to the cervix and has altered position. Either that or just a different midwife feeling things differently.
My old midwifery testbook says around 0.5cm - 1cm an hour is "normal" (whatever that is). In my experience dilation is all very well but not if the baby's head is not well applied - then you get all sorts of variations in measurement as a cervix not well applied to the baby's head (or vice versa) is much more easy to stretch and then you get an overestimated dilation.
Morningpaper whilst it may appear confusing to me it still reads the same in terms of labour
at 7h30 you were just in established labour
and 2 or 3 hours later you were on the verge to transition but not ready to push, still some woek to do. (between 6 and 8 cm there is very little) - also some MWs like to talk positively (!8 cm may (?) have been a slight over-exageration)
What happened next though?
Yes MWs have different readings on same woman ALSO you can actually "go backwards" in dilation too... I have seen 5cm go down to 2 !
I think that all was fine but maybe - considering earlier replies you had either dilated then retracted slightly because of baby's positioning or it was to do with a difference in midwifes techniques. Hope that you are feeling a bit better about it all.