Traditionally, a “batch” is what is made at the same time, same run, same ingredients, same conditions, same temperature, etc. so all 500 grams should be brewed at once.
A simple brain fart when weighing the raws could fuck it up. Adding a little too much BB would dilute it. Measuring out a little too much oil dilutes it. Forgetting to clean the kitchen counter and KitchenAid stove before brewing could introduce fuzz in the 2nd half of “Batch 103”.
Its pointless to put batch numbers on vials that are made at different times. The product samples should be resubmitted but obviously the raws sample is still valid.
If he wants to fuck around with that (which douchehead no doubt will do) he’ll get bit by it when there’s a problem with one of his brews and he has to recall ALL of “batch 103”.