Newbie question to TP running - looks like we will need 20TP each to reach Silver. I'm looking at LHR-EDI. According to the TP Calculator on BA.com - Economy "Low" gets 10TP, but lowest only gets 5. Whether I pick Economy Basic or Plus when booking, it still shows as booking into O class which is only 5 TP each way. Picking flexible books Y at a price I might as well pick CE.

Just wondering if there is a way of forcing a slightly higher fare class to get the additional TP?

Thanks.