Matt,
Just like most other RE responses, it depends. Right now Charlotte has been a pretty hot market in certain areas so those numbers may make sense but other areas, like the west side of Charlotte it may take a bigger discount to entice a buyer.
Also remember that the 70% of ARV - repairs is what the BUYER wants so you will need to factor in a number lower than that if you expect to get a finder's fee. Right now there is a glut of newer properties at fair prices but it you can find a good deal it should sell.
I know personally we are having difficulty finding good properties at a good price, especially since the institutional investors continue to buy properties so any discount on those nice properties should find you a buyer.
Overall it is important you find a location that buyers are looking for and if you can find those # you should have a shot. Give me a call or email if you find one, I am always looking.