OSAP with OGS question

Hello everybody
I am expecting OSAP funding this term and let say I am also applying for OGS. If I get accepted by OGS (big if) how much would that drop my OSAP "grant" section?
Meaning if my grant OSAP was x and OGS will be y, will my new OSAP grant become x-y right away? Doesn't seem right, considering the effort I had to do to get accepted (if I did) into OGS, and I end up with the same money anyway!
Anyone did this and know what will happen?
Also if OGS came mid-term would the extra part in the OSAP turn to loan?