"42. At this stage of these proceedings, we conclude that it is at the very least arguable that the lower prices offered to BE and EME should also have been offered to ECSL and that EWS's failure to do so arguably constitutes an element of the price discrimination as found in the ORR Decision. For present purposes, we do not have to put it any higher than that. The test to be applied under Rule 40 is whether the claim is bound to fail. It is in our judgment at least arguable that EWS should have offered the lower prices to ECSL, and therefore this part of the claim is not bound to fail."