LEAP Bridge Concrete self-weight deflection

I'm using LEAP Bridge Concrete to design a prestressed box beam.  In this design we are concerned about haunch heights.  I was checking the beam self-weight deflection shown in LEAP vs. the AISC equation and another in-house structural analysis software.  The AISC and in-house software deflection values match.  LEAP deflection is more by about 7%.  I have verified reactions and moment, so input weight is the same.  I am using the same bearing to bearing span length and same E.  How is LEAP calculating the Beam Self Weight at Release?  

Thanks