Hi Likas
It looks like you have a difference between the in-house production time defined on the material master and the times defined on your routing.
You should check carefully the values defined for the operations on your ruting and check if they match the in house production time on your material master. The document previously suggested explains how to run a scheduling test on your routing to check the results.
At last, you can run transaction CA97N to copy the times defined on the routing to the material master.
BR
Caetano