Just saw this now... But if you spend enough it may not be worth it downgrade.... You won't get the 2% back. Once you hit $2750, you break even.
I just went to Costco to get my membership.. I upgraded and got another $20 Costco cash (which I applied together with the first $20 towards the upgrade). She told me that if my check from the 2% back is less than $55 I could come to the store and they will give me the difference. Does anyone know if this is true or not? Should I rely on her? Although I guess I could downgrade later just in case.