Alchemy and enchanting seem to be really simple processes in that world. You don't even need any equipment, just the skill and that's it.
Either the MC is scatterbrained or the author is. In the same chapter Meria diluted the higher potency potion to make less suspicious lower strength ones, to avoid attracting attention. Yet shortly after she's selling amazing enchanted magic stones and more potions, plus ordering a never seen before device from a blacksmith and explaining how enchanted magic stones can make it work. Unless she was planning to become an alchemist again, she should have just sold the intermediate potion alone. Tell the merchant it's something her parents left behind and told her not to sell unless absolutely necessary. She couldn't sell more in the future to stick to the story, though. But now she has got no story and guards knocking at the door.
After writing that, I believe both the author and the MC are equally scatterbrained.