Neo currently gets a mix of P@H (weaning off of these as fibre is too low), Excel and Science Select.
We take a scoop of each and as the Excel are so small and the Science Select so big, it sort of levels itself out a bit.
I think as long as they are eating lots of hay and haven't had dramatic weight increase or loss, then what you're feeding is just right!
A friend of mine and her Mum ate the same thing for a week, drinking the same, doing the same activities and her Mum lost weight but she stayed at a steady pace. They originally weighed the same within 5 pounds...
Weird but I think it's down the individual bun?!