Aye, that seems to be the case. We had our fleet certified to 10 minutes to be able to fly into places like Innsbruck which is virtually impossible with 5 minutes limit (not that we've flown there in the past 8 years). However we took over two ex UAL and those are not only limited to only 20k lbs thrust rating but also to 5 minutes (and both were in a very poor state, we had to extend the take-over D check by 6 months to fix everything required).