I looked high and low before buying my bus and I could not find anyone that would lend on a seated bus, unless it was at operator type prices, say $4,000 a month payments. The current wisdom, substantiated by my resesarch is that the banks will lend only on a converted bus, with an appraisal.
And yes, there is a very large difference in value betweenn seated and converted, either RV or entertainer.
