This is why I deal with Justin at communitydiscs.com. Any discs that he is unsure of the weight, he personally scale weighs and puts a sticker on the bottom with the scale weight. I have had this issue with various other stores, but never from Justin.
2013 Vibram Disc Golf Street Team
/Vibram Tester Team
/2013 DGCR Travel Tag #50
Last ACE: 10/25/2013 - 170g M Sole
Metal hits since last ACE: 0
"In general, I get strokes by not playing as bad as others." - Craton