Sounds like it’s still not running right.
Have to provide more data. I presume a fancy coach like that has a full complement of gauges? Are you making full boost, what are egts, is the trans downshifting properly?
Could be rail pressure, weak FPR blowing off too early as well.
It’s wholly improbable that you plugged up 2 air filters in a week unless you drove thru the great dust storm of 1929 or a swarm of locusts, lol. What did the filter minder say? What did the filter look like? Did the mechanic actually ever look at it or did you just have a quick free phone call w him?
Sounds like this is a new purchase and no previous history with the unit?