Supply Simulation returning erratic results

Hi,

While executing Supply Heuristics we are experiencing erroneous results. For example, in our case if the Dependent Demand is 100 at a location and with Stock on Hand = 0, my net demand =100. Now if we are placing a stock of 80 and simulating we are finding that the values of dependent demand are getting changed altogether, when we are expecting a net demand value to 20. This things are well described with the following screens taken chronologically.

I am not able to understand why this kind of result is turning up suddenly when everything was working fine and as per expectation even till last week.

Regards,

Indaarjit