Mercenaries mythic difficulty

So I want to play level 260 bounties in mythic boss rush but when I try to up the difficulty, level 155 is the maximum I’m allowed to go to. Anybody know how I go higher or why I’m restricted ?

Edit: I’ve found the answer to this (thanks Old Guardian) and this seems to be a really crass piece of design.

The max level this week is 260, because I didn’t open my spare mercs packs the first week or two, I was operating well below the max possible. You can only set the diff one week up to 40 levels higher than you did the previous week.

Would be much better if you could catch up by a process of something like “You can up your diff by 60 or 80 on the previous week, or to the maximum level available if you’d operated at that for the whole time, whichever is lower”, so my max last week was 115, the maximum level available this week is 260, allow me to go to 175 or 195 this week and I catch up to that maximum level in a few weeks rather than never.

One thing to worry about is that the minimum level is 100 less than your maximum. For me, that means some serious danger that next week there will be some runs that I can’t complete at all. Considering that “first clear” rewards much more renown than “repeat clears”, that could be significant hit to incoming renown.