Dots vary from batch to batch, so some accuracy might be only if you got the same batch as the one with decoding table- it never worked for me, instead of series 1 and 2 with extra barcodes I am all touch'n'feel...
If used, I see weighting only as preparatory step before touch'n'feel, check the bag approximately for the contentand then touch'n'feel for 100% sure - WhiteFang reviews are very helpful in this.