It IS a disadvantage for American operators when there are remote obstacles to clear OEI, thus RTOW limited. However on modern engines there is really no basis in technical fact for the 5-min. limit.
I used to do test cell runs in which we repeatedly held rated TO power longer than 10 minutes, and while I can't say it was good for long-term retention of EGT margin or SFC, there was NEVER any reliability issue.
Thus - the beancounters are not delighted by the prospect of early removal of a performance-limited donk for seal refurbishment, but flight crews of a modern engine should not hesitate to use TOGA as required.
