True. It has to be done by phone. And even though it should work, it does not (at least, it has never worked for me), and the agent has to escalate it internally and I think they create an MCO (miscellaneous charge order) and exchange the ECV value being redemed for that and then apply the MCO to the ticket, or something like that...it's a convolluted workaround the ECV redemption towards taxes/fees not working, even though per the T&Cs it is valid towards that.

Oh and re: YQ on CZ, perhaps it is higher if going accross Pacific and lower if not crossing any ocean and just going from EU to Asia (or vice versa). But for that I can tell you that it is either $0 (as I think it most likely is, as the ~$50 YQ I have I think is SU, MU, KL and OK on it, not CZ), or if not $0 then negligible.