Sharing my valuation with seller

[Eric Booker]

I'm in negotiation with a couple of multi family apartment owners. They have owned these properties for a long time and have self managed. My price is directly derived from my valuation, and these owners have mentioned that the cap ex, maintenance  and management allotments are to high(I'm using the standard %'s) which makes my offer to low. Should I share my valuation? I want to be upfront and honest with them, but would like experienced investor input on this matter.