Report writer availability vs UI resource availability major discrepency

My telecom operational people are calling me on the stats I'm reporting from Orion. They've pointed out a massive discrepancy between what the UI reports and what Report Writer reports:

This is an example from The web UI for one of their routers

I'm specifically looking at the "Last Month" availability.

They don't mind the 94.007% available stat

HOWEVER, they take great exception to the number that report writer spits out:

I would like to see the SQL that the UI resource uses to calculate the availability so I can compare it against the Report Writer SQL