I'm very, very new to IHG BRGs (only done a couple of Choice ones). Let me use a hypothetical example here:

HI Adv Pur Rate $139
HI Flex Rate for Same Room Type $179

Does the lower rate I found have to be lower than the Adv Pur rate, or would it work if I find a cancelable rate in between the $139 and $179? In other words, if I reserve the flex rate at $179, find a non Adv Pur cancelable rate of $149, and put in the claim, what's the chance of it working? Thanks for any help.