If you try to re-torque them to the same value while still tight it will take more to overcome the standing friction thus the need to loosen first. If you were going to be adding a considerably higher torque number then you could start out with them tight. Also when it's getting close to tight it's best to try to get it all in one motion because if you stop when it's close and try to start again you have to again overcome the standing friction, which could result in a lower torque number. I don't know if I'm making myself clear or not, I'm not great at describing things but hope this helps.