Made an offer on a for sale by owner

[Andres Cardenas]

 Hello BP! Drove by this house in the south mountain area today and saw a for sale by owner sign and  decided to shoot my shot(for the first time). It's a 2/1 single family 1,106 sq ft, condition from the outside doesn't seem to bad but was not able to see the inside because it is currently occupied, ran numbers and comps and came up with a offer of $140k and got denied. Before I even offered she mentioned they've received several offers,highest being $280k. I find that hard to believe since nearby comps are selling for $220-$230k for 3/2s fixed up ( my plan was to convert the carport in to a room so it can be a 3 bedroom house). Told the lady that seems way too high and I mentioned the comps nearby. I asked if I can see the inside so  I can give her a more accurate price but she wanted to end the conversation right there. The lady did mention it was in good condition but it would need paint and some updating Here are the numbers let me know if I'm missing anything and if you have advice related to this please let me know. 

If I would have tried to flip it ( would need a partner for the rehab cost and 15% of purchase price, splitting the profit 50/50 with me providing work and the deal) 

Arv: $220,000 ( as I mentioned there were a few comps that sold between$220k and $230k in the past 6months)

Repair costs:  estimated $30k ( I have no idea what the inside looks like but I assume it would be trashed)

Hard money: 85% ltv $119,000

                           - at 10%: $11,900

                           - 2points: $2,380

Holding cost: 4,500 (3 months)

15% of purchase price: 21,000

all in for $188,780

if it sold at $220,000 that's $31,220 profit, $15,610 each  with a 30% return for my partners money.

Or I would have wholesaled the property.

Am I looking at this correctly? What would you do differently, and any tips on speaking with sellers directly?

I will be following up with seller if its still for sale in a week. Thanks in advance!