I bought in the meantime 4 motorbikes in Pattaya, 2 on visa exemption and 2 on Non/O visa and had never problems to get the residence cert. A nice lady in a motorbike rental shop always doing for me the yearly tax/insurance cert. as well as provide me with residence certificates for all reasons. Cost me just 300 Baht service charge.
I think it’s not true what you are talking about. The rules about financial requirements just like this:
(a) Applicants must have money deposited in Thai bank located in Thailand with the amount of not less than 3 million Baht; or
(b) Applicants must have money deposited in Thai bank located in Thailand with the amount of not less than 1.8 million Baht and have income with the amount of not less than 1.2 million Baht per year. Once the applicants enter Thailand, they must have accumulated money deposited in Thai bank located in Thailand not less than 3 million Baht within 1 year.
The money in (a) and (b) must be kept in bank account at least 1 year before withdrawing and, within another next year, the money must be left in the account with the amount of not less than 1.5 million Baht and can only be spent in Thailand.
If you don’t want to visit everytime the immigration office before you leave Thailand it’s worthy to apply for a „Multiple Re-entry Permit“. It cost 3.500 THB.