Whoa, that's pricey!
I just did my big Nouvo seat, only new vinyl, I chose cool-looking snake skin, cost me 200 baht.
The seat of the CRF needed a bit of foam. I had some black, sturdy foam glued in where I sit, plus new vinyl, 250 baht.
All done within half an hour or so, clean work.
Down here they're not used to foreigners and I'm probably paying the local rate.