1. The value of Ah calculated by STAAD.Pro does not match the hand calculated value. It is less than what has been obtained by the hand calculated value.

 Please check if you have entered the DT parameter representing the depth of foundation. As per clause 6.4.4, the code
requires you to reduce the value of Ah from 0 at the surface to 0.5Ah at 30 m depth and below. The reduction of foundation lying between the surface and 30 metres are to be interpolated linearly between the boundary values.