On the SM 2.1, when you go for a blast and it goes into record mode, and press the mode button while holding Recall, it tells you MPH at which the lowest 02 and highest KR was recorded. I notice sometimes it says two different numbers for the MPH. Some times it'll say the same MPH on both sides, but other times it says two different numbers. Whats the deal with this? Which number is which? Why does it sometimes have two MPH values? TIA