If the lender asks for something that does not impact assignment results, is it wrong to comply? I could provide this thread showing most appraisers would use the 1004, although at least one person would use the 1025... HBU would still be SFR with adu. There are technically 2 units. HBU would still be SFR w adu...
The the one person TMD .. is extrapolating reason to use of 1025 form for a house with an ADU, because the Fannie selling guide says an appraiser may put 2 unit properties on a 1004 FORM. Does that make any sense?? The better question is why would you do it...even if you "can" do it, why would you do it when the HBU ( SFR) clashes with a small income property form intended for 2 -4 unit properties whose HBU one assumes is small income use.
Each form asks for HBU of the subject. If HBU of subject is not small income property, why are you putting it on the small income form?
Two separate homes on a lot can be a small income ( duplex) property, if HBU is such. In that case, it would make sense to put it on a 1025 form. But you are saying the HBU of subject is a SFR with ADU ( and property characteristics support that )
Did you research to find out if the subject as a SFR with ADU is selling for more than 2 unit income properties in the area? That would be part of supporting your determination of HBU of subject.
Your lender , or at least the person you are talking may also be an idiot about asking you to put it on a 1025 form. Sometimes they simply don't know, they are not appraisers. Every time this has happened, I politely point it out and they are grateful, because a lender submitting a property on a wrong from can cause problems for them ( and the borrower) .
As you noted from above in your answer, most appraisers would use the 1004 form, and peer
practice is one of the standards in USPAP .
The lender is asking for something that does impact assignment results, (correct form for property type and HBU) so that answers the question about compliance.