I disagree with using brute force to remove the mag floorplate. As noted/suggested in my previous post the tabs and associated recesses/slots of the floorplate are designed for installation of the floorplate on to the body of the mag not for removal. The angled/beveled tabs and corresponding recesses/slots serve the purpose of minimizing distorting the plastic.
Using brute force to overcome the squared side of the tab and corresponding recess/slot on the floorplate is like fitting a square peg into a round hole. The end result is damage to the tab and recess/slot. That would explain why subsequent efforts to remove the floorplate would be easier.
This damage may eventually appear as a bulge at the floorplate causing seating issues of the mag into the pistol or shortened life of the floorplate.
Generally in mechanics using a high degree of force is not a good thing. Frequently it means the method is incorrect. I’ve lived long enough to have made enough goofs.