So just tried to build a complex multi-segment (14 segments total on ITA) and I specified booking class G and every option came up all 14 segments as Tango G for a total price of $1269 CDN. I then changed the booking class to V and all of them came up as Flex V for $1599 CDN. This is being a big PITA for trying to find decent flights for EYW now. Because I know that AC has G fares available (I looked each up individually on their website) but can't specify Flex G in ITA.