Triple prices in the entire town over night? What could the blacksmith possibly have done to generate that outcome, when the majority of that money should be material cost?
Bear in mind she's a blacksmith that was currently working on something (ergo she was in business). Being commissioned to make a piece of armor and a half should not be a sudden surprise for a blacksmith.
If they had ordered 10 or more full plate armors, decorated with ornate brass roses and golden spikes on the shoulders... I could understand the type of mad inflation they brought about. But they ordered a piece of armor and a half, and a weapon. In my mind such an order is mediocre at best ~ for a blacksmith who is in business in a town that is buzzing.
You could argue that the special thing about that order was the "get it done faster" part, where they dropped a little extra. But "upgrading to level 2" with an order that should come in every month or so? I doubt that.
Adam wanted to jangle their nerves somehow and drain their income in the process (which a GM needs to do all the time to keep the party grounded). This was a fun way to do it, but also !
P.S.: If they had visited 10 stores and dropped 300-500 gold in each... I could understand that inflation a lot easier