Taking offers on wholesales

[Terry Royce]

How do you take an offer on a wholesale property? Do you just have the buyer sign an assignment contract, drop off a check, and then you only sign and ratify the best one?

Which brings me to the second part of my question. I had a buyer make an offer which was lower than my contract price, but I had a feeling my buyer would budge. He mulled it over for the night then agreed today. But by today my buyer decided on another property.
So in taking offers that are less than your current contract price can you just word the assignment to the effect of
"In consideration of an assignment fee, which will be the difference between the Assignor's purchase price and XXXX amount (sale Price)."

I'm just wondering if you HAVE to specifically state the assignment amount so that you can take offers, take it to the seller, and avoid loosing a deal like I did today.