I still get phone calls three months later due to moves he made that I was not aware of from buyer's and seller's.

I can't speak for other states.Lease options are great, but I normally see them as a 2nd or 3rd option after the seller refuses a cash offer. 

I'm worried this offer will insult the seller.

Our title company will allow us to do a dry double so long as we inform the seller that their funds are coming from a third party.

Run the numbers of the comps, call the previous buyer and seller agents for those properties and ask them why they think the property came in at the value it did, and have that data ready to provide to the appraiser for the appointment.BUT -- don't make it seem like you're trying to tell the appraiser what the value is.

I concentrate on flips because it is a sellers market and I do my own work which keeps me happy and eliminates a lot of competition. 

Clearly the seller / agent is someone who know how to prepare a sales brochure but needs to double check their math.Hope this helps.

I have been considering getting my hvac certification cause of all the money I spend on a/c contractors.I suspect 5 years from now there are going to be a ton of motivated sellers trying to get out of all these low cap rate, marginal deals.

Do I continue with the deal knowing that the cash flow is lower than expected but just get into action or wait until another deal and continue waiting knowing it's a sellers market? 

In most cases, this should serve as Bonafide Proof of what the Property is Worth, as it reflects what a willing Buyer and a Willing Seller agreed to on the property - thus that is the textbook definition of Value.     3.