I'm not sure of the exact timelines but from my experience they grow about 50% each time they moult when very young and they moult often at that stage. I have occasionally seen very small ones on the side of the tank, eating the biofilm but I don't think they are newly hatched as those are usually born somewhere 'safe' away from view, like moss etc and they don't move far from where they hatch at the start.
Your 1mm per week would certainly be about right but it would be proportionate to age so the younger the faster they grow! It will depend on how much they eat etc as well and they don't all hatch at the same time either so you would have to set up some kind of laboratory setup with just one berried shrimp to find a precise figure, and even that would also depend on water parameters/temperature to be of any reliability.
I would just get a glass of your favourite drink, sit back, and watch the new ones and enjoy! I know this doesn't really give you the answer that you are looking for but I don't think that exists as there are too many variables??