Ashutosh,
Availability checking is 'date driven'. System calculates the availabilities at a particular moment in time. You can display this in CO09. I don't know the dates of your demand elements, so I can't really answer your question.
It sounds like for your availability checking, you wish to only use stock as a supply element, and no other supply elements, when determining available quantity. It also sounds like you do not wish to allow safety stock to be used when calculating availability. Please confirm.
Please display a screen shot of your CO09 for this material. While you are in that screen, select "scope of check" and post a screen shot of that as well.
Best Regards,
DB49