STAAD PRO ANALYSIS RESULTS DOES NOT MATCH WITH MANUAL VALUES

I would like to know what is wrong in my model iam using Staad Pro Update 5,using BS 8110, the selfweight of the slab is 3.6kn/m2, finishes 1.8kn/m2, partition 3kn/m2(Total Dead Load 8.4kn/m2) and live load is 4kn/m2.

Wall load on the outer beams is 10.35kn/m. The bending moment values of highlighted beams as shown on the attached picture are from Staad pro are very small compared to those of manual computation.

I need a help on this and i have attached my Staad model,floor level 4.05m

7288.Structure1.STD