Hey BP fam, I’m working on get my first deal and this is what I’ve run into. Is 65% x arv - repairs, a good estimate to value a a multifamily rental property ? 

I got a call from a motivated seller/ seasoned landlord he has multiple properties with 100% equity. He asked for an offer right off the bat. He said go check out the property and give him a price. So i go check out the property next day . The property was a 4plex and built in the 1920s, and I didn't go inside but just from the outside it was a rough property so i gave him a range on what my offer would be depending on repairs. I estimated a full gut to be safe. I did the (65%x arv - repairs) formula and he was pissed. He said I need to learn how to value properties better or I’m not going to get a deal from anyone.

So I’m just wondering if Im takIng the rIght approach on preparing my offer price. is 65% too low , am I over budgeting in repairs, or was my offer fair? 

I'm not flipping or wholesaling. Just trying to get a rental property using the BRRR strategy.