I'd take a punt to say that the codeshare wasn't worth it.
Logan have set fares starting at £80 one way which is a damn sight less than BMI did if I remember correctly.
Only time I flew the route was via a codeshare, connecting onwards from BRU and that was at ludicrously cheap fares - so much so I suspect the high price for those onboard just doing NCL-BRU sector was subsidising it. Plus BRU would be very much down the list of connecting airports I'd want to be stuck in!
Will they make any money? Who knows, it'll be tight I'd suspect!