I will come at this another way to try and explain my point.
The engine has a limit of 5 mins at TOGA (850 deg C), at the 5 mins point I select CON (750 dec C) how long is it before I can reselect TOGA, and what is the time limit when I do? I could also ask how many times am I aloud to re-select TOGA on a single rotation. Is the 5 minutes a cumulative total or a total for a single application? None of this is mandated anywhere, we have to use our common sense.
According to the letter of the book, it would be perfectly acceptable to use TOGA for 5 mins then select CON for 30 seconds and then re-select TOGA for a further 5 min. However, we don't live in that world and in practise most of us would find this unacceptable abuse of the engine.
So what exactly is my point? My point is that there are very few absolutes in aviation. And with a little extra knowledge we can make educated decisions about such things. Hopefully in the full knowledge of what the limits are, and the likely consequences of operating beyond them. Its why we get paid the big bucks.