The formula gets a little complicated but here is the stuff that we can share.
Each hub is assigned a daily hub differential that is based on roster size, pilots on leave, and some other components to determine an active roster size. The differential is there since each roster size fluctuates and we want to make the challenge a little more fair.
For each pirep that meets the criteria the hub differential is multiplied by a base number. That base is basically 2 for Vatsim flights and 0.5 for non-Vatsim flights.
So as an example,
PiRep flown on ACARS for BWI-BOS for an MCI based pilot.
Pirep OFFLINE - Multiplier: 0.5
Final Points: 2.1