My instructor always told me to NEVER say "to" as in "Climbing to two thousand five hundred" as it can easily be mistaken as "climbing 22500" although why a PA28 would climb to FL225 is out of my knowledge
lol!
But best be on the safe side, if you don't use / forgot the correct R/T, just spend 30mins or so re-freshing your memory on CAP413!! Surely thats not too difficult for you? Not to be mistaken for, surely thats not 2 difficult for you
Regards as always.
Martyn