Can you post a screenshot of the following things from your SH 0.9.8 software?
1) The full daily data screen on a day where the AHI computaton seems to be incorrect. Be sure to show the left side bar with the AHI prominently displayed.
2) Then click on the "Events" tab in the left side bar. The list of types of events should now be showing and by each type of event, there is a number that indicates how many of those events are present.
With this information, it may be possible to figure out what SH is doing and what the correct AHI should be.