MMBE Shows stock properly in US gallons but shows negative in KG.

Hi Gurus

I am new to IS-OIL Concepts, we have a material which when was received using a STO to quality stock the API value was entered and the calculated Quantity in KG. and when it was approved from Quality a different API value was entered because of which now the stock shoes up A negative value in quality in KG but not in US gallons.