To speed up the process for any pressing service, it is always best to have the paperwork ready to go.
When submitting through the dealer account of a pressing company you sacrifice convenience for saving some money. You cannot track the books, you don't have access to the notes (most guys will not do a copy/paste for 50 books) a few books, yes. If the presser has to fill out the paperwork it can add significant delays.
As long as you expect these things going in you will be OK. Be aware of the trade offs when submitting under someone else's account because (technically) they own those books while at CGC, you cannot call to get info on that invoice.