Yes, in Maryland average profits, at least in my personal experience with my flips, is in the $30,000.00 range. There are other variables to take into account and by my experiences some of your estimated costs are low. At least as the Realtor for my own flips, I can set my commission so I can make up for some numbers at time of sale by up to 2%. As a rough number in calculations on the resale side of the transaction, I use 12.5% for sellers costs at settlement.
Due to the current competitiveness of the local market the 70% rule is a hopeful number that is a rough guide and not written in stone. I walk away from more potential flips than I purchase due to deals that on the computer look great but when viewing the property in person more expensive repairs are often found. In Southern Maryland, in a lot of instances, there are hidden costs of a well or septic system replacement that also needs to be accounted for when running numbers on potential purchases.