Maybe I can clarify. All marble companies produced many marbles that would not pass their quality control process for a variety of reasons. They might be fractured, out of round or misshapen. Or sometimes, workers on a shift might have been too beat to package their quota and the marbles got dumped on the factory property. I am sure there were driveways in WV that had as many marbles as stones in them. The discarded marbles were used as fill under cement floors, in french drains, etc. After the factories closed many of these marbles were excavated by diggers and found their way into the hands of collectors. An example might be Akro's Popeye Patches. The vast majority of these types were discarded because they did not form corkscrews like they were supposed to, but they were dug up on the factory grounds and many of them are collectible today. I hope this helps clear up your confusion.
It's important to remember that marbles were made as children's toys and were used to actually play marble games with. Companies prided themselves on the quality of their marbles - their roundness, solidness and eye appeal. Hence Akro's marketing lingo "As straight as Akro flies". The last thing any kid would want is to spend their hard-earned allowance on a package of marbles and find out that several of them were egg shaped and useless for playing marbles with. Such a thing would certainly cause a company to loose favor and market share, hence the discards.