Yes, some builders do offer these rates if you use their in house lenders 

Hi, I’m under contract on a property in Joshua tree California that we are going to upgrade and list as a high-end STR. the home is currently a mobile home, but we are going to do a 433a registration to have it recognized as a manufactured single-family home.the lender we had lined up all of a sudden stopped offering DSCR loans on rural manufactured homes (they literally stopped offering it THIS week:(The seller is willing to seller finance, but only for two years…does anyone have any suggestions on the best way to go about finding a lender for long-term fixed rate DSCR on a rural manufactured home. 

Premier Members Credit Union is a solid all-around choice since they offer HELOCs for both primary residences (up to 80% LTV) and non-owner-occupied properties (up to 75% LTV).

"Put it in your offer".

Hey Emi, welcome and congrats on putting in that first offer. 

One of my Electrical sub only offering me 90 days warranty on one of our projects.

Offers.

What kind of offer should I make?

Yes make your offer by using a binding contract.

Appreciate the offer!