I have seen a lot of discussion on bad cups, potential contamination on graduation marks incorrect. I needed to get some cups so I can mix more than the 22oz of my PPS cup to have induced epoxy ready to go for a days spray ahead of time. I have seen a few say they use TCP Global and it was easy because it was amazon so I got two sizes. 64oz and 32oz. Just to be sure before I trusted them I checked both against my 3M and both TCP sizes were off. I tried mixing 1:1 water using pps to measure parts and two different measuring cups and all came out the same. The 32 out cup I mixed to 5 the first 5 is correct. the second 5 the volume is too low. on the 64oz I mixed to the 4 mark. Same deal first mark accurate second 4 volume is too low. I'm not sure what close enough is, but I decided to return the 32 oz and place my own sharpie marks on the few 64oz cups I got for 1:1 mix. I just wanted to pass this along. I'm not sure if its always been off or this is just a miscalculated batch.