The worrying thing about BOS is the Sept start date.
BOS seems to struggle a bit more in the winter, even the likes of LHR and CDG see reductions in the winter, so, I’d be surprised if PY still ploughed ahead with a 4 weekly winter flight, especially now it misses the bulk travel period in the summer. That’s not to say they could launch BOS succesfully next summer after the other 2 routes have bedded in a little?
Suppose it’s a wait and see, but let’s face it, 3 new TATL routes from BHX, the same at STN and then CDG with no previous experience in one go was always a tad ambitious, not to mention they don’t physically have the aircraft yet either.