How the hell do you know exactly what they're doing? Your presumption is misleading.
They may have better scam IFS, they may even try to dump prices at a loss or zero profit to chase you away.Trying another plane in similar config and IFE by your company is the only way to know the exact difference.
A340-600 is a great plane in AE, it can make similar money as 777-300ER.
Only A340 that's not very profitable is -500 because of the way AE doesn't recognize the max seats - 3 class config problem, and it's a gas guzzler just like 772LR, ULR doesn't make sense anyway.
(IRL A340's four engines would mean much higher maintenance but that's not so in AE)
772LR is great for ULR which does make sense. Especially for Australian, South African, and Japanese carriers.