I am flying MAN-CRW soon, and mulling over my choices. I'm thinking about buying a Y fare on US and upgrading it via GoEnvoy. Alternatively, I've been lucky in the past with some good R fares MAN-EWR. However, these seem harder to find, with Co.com often disagreeing with Expertflyer as to whether there are any seats left.

For example, CO21 on 31st Oct has R4 according to Expertflyer, but CO says not.

Am I trying to book way too close to departure to have any luck?