Is This Just A Coincidence?

I have a Remed Auto Set Spirit and I was just going through some data from the last few weeks and I have noticed a recurring pattern. It seems that everytime I have recoded a high AI figure (usually over 1) I had gone to bed early - around 10 pm. The later I go to bed the lower my AI figure seems to go. Is this just a coincidence or has anyone else found a correlation between their bed time and AHI figures.