Yes, this is going back a few years, but for some reason UuA when bought straight up are charged against Plus fares, but thereafter you can UuA against Basic too provided it's N or above. So buy the Basic fare online, get the e-ticket, then UuA. If necessary you can call within 24 hours and fix anything without additional charges or even get a full refund.
And it will get the CE baggage allowance.