You CAN fly it for 5 minutes in that power band, then lower the lever, then go back into it.
BUT! You will not make it to the engine overhaul on the suggested times - the engineers will pull it well before then - maybe TXMSN making metal, maybe turbine creep, maybe a lot of things.
The TBO is worked out on 5 mins of takeoff power per 1.3 hr flight, or thereabouts. Thus they expect you to pull the power maybe 1500 times during 2000 hrs of flight. If you do it 1500 times in (1500 x 5min) it is all used up and you have some expensive servicing due.