The reason to break them and then re-torque is that an accurate torque reading can only be made while the bolt/nut is moving. You can't get an accurate reading without it moving.
No, there are two kinds of torque, static and dynamic.
Static is higher and what you call "breakaway" which is how much torque it takes to start the bolt turning.
Once it turns, then you are measuring dynamic torque, the amount needed to keep it turning, which is slightly lower.
But if you verify the torque by just tightening only, you won't stretch the bolts again and the verified torque should be close enough if it was static vs dynamic... It's better than stretching the bole more if you don't have to...
