BOM sorting issue!!!

My problem is this....Sometimes when I open a drawing, the BOM will revert back to sorting by QTY rather than by PART NUMBER...which is what the company uses here.  I have read posts about changing options to "lock" the BOM, but I gather that this will cause issues when people open the same drawing or model later and add things to the BOM.  We currently use SW 2012 and we use the PDM...so is there any advice or help out there about locking it to atleast sort by PART NUMBER and not revert back everytime I check the drawing in and open it back up?

Thanks for your help in advance,

Chance G.

SolidworksBill Of Materials