Seller usually gets higher price (much higher than appraisal) an

Yes, you can pay for a third party to do that for you but with a cost. We charge them monthly escrow payment to cover the homeowner insurance and tax. We have accountant to do our tax every year, to file tax the only thing she needed to know is the amount of interest we got and buyer's SSN, not that complicated.

Also, you can sell the mortgage to another investment firm, we constantly get those letters, but it is at a dicounted price, as long as the buyer pays the payment on time we have no intention to sell it since 6% return is ok for us.