Does anyone happen to know what the Tax/fee/surcharge increase is WT+ to CW? I priced a multiclass MFU booking on BA.com and then called to book it. The flights are to BOS and are CW to F out and WT+ to CW back and the price I was quoted was different to that on the site. I booked it anyway and was thinking it must be the difference in tax between WT+ and CW on the inbound.

However when I did this last year and priced it online first, the phone booking came out cheaper. So does anyone know the actual tax difference?