I'm not going to argue against the test kit, it can't hurt, you just have to realize the limitations. Many of your hardcore NW cichlid keepers try for wild caught or F1 fish just for the reasons you mentioned. Your more serious breeders will outcross to wild stock when need be, then breed back to obtain their goal, with a fish that is stronger genetically.
The fish that are commonly sold in corporate owned & run shops usually come from a commercial outfit, many of which are in Florida or California, who do not give a care about the inbreeding & genetics behind the fish they sell. The Asian imports are just as bad. Your smaller independent shops are the ones who will deal with local breeders, these are the ones who will outcross & such for a stronger fish.