Data point: On flight AC33 (YYZ-YVR), it's a different scenario. Once you "sign-in", you get wifi automatically, no option for ultimate flight pass. I guess it's YMMV depending on aircraft and/or flight.
The only thing consistent with AC is inconsistency!!! I just wish they told us the actual plan for this rollout so we knew what to expect so we could plan accordingly.
It also appears that the 1 device at a time rule is still in effect. As soon as I logged in with my phone my laptop lost connectivity.