Manufacturing large quantities of product to tight specs could be both tricky and expensive. You either need to have your fabrication equipment built with those tolerances in mind, or your quality control need to throw out large amount of out-of-spec items into the trash can. That is - if you have quality control test equipment that could test to those tolerances large amount of the items. Think about quality of LEGO vs other no-name-brand blocks that hardly stick.
I think ball production was outsourced to a large manufacturer, who never had clients requesting any strict tolerances. They, probably, don’t even have any quality control equipment at all. They have a person picking a ball of two from each batch and measuring it manually. They, likely, do not need anything more sophisticated. Try to imagine DollarTree complaining that $1 play balls don’t meet +/- 10% weight specification.
In addition to that, the mass production facility, likely, has their processes vary more than a smaller operation that produces samplers for the potential clients…
I am a bit disappointed too, but VRC was never meant to be easy. If those tolerances are, really, that bad, or even worse between the different batches, then the game just turned out harder than anyone expected.
What I afraid of, is if a team or club will practice all season long with roughly similar balls from the same batch and then discover, just before the states, that other batches’ balls have significantly different specs - that would be some bitter disappointment.
I think we should sample the balls, post the measurements, and create a size / weight distribution chart. If balls are out of declared specs then, at the very least, game manual should be revised to reflect that.
However, most of VRC participants are future engineers, and will greatly benefit from learning how to figure out clever ways for handling such situations. I am sure there are at least a few good way.