If the meat is still wet when going into the pan, it will stick. Albeit, in a well seasoned cast iron skillet, I have scrambled a dozen eggs, fried eggs, etc... with nothing sticking. Could be the pan isn't as well seasoned as you may think. Try pounding or really rubbing the seasoned flour well into the cube steaks. lay them out on a cookie sheet or on a rack with space between them. Then, when the pan is ready, do a final light dredge in the seasoned flour, shaking off the excess, and then fry.