Continuity mistake: In the scene where Frank's mother spills red wine on the carpet the stain shifts altogether once the next shot shows his parents dancing. (00:12:00)
Continuity mistake: When he pretends to be a doctor, and a he has to give advice on what to do with this patient, a woman gives him some kind of tool. He holds it in his hands, and towards his face, in a 'thinking' pose. Then the camera changes and the object is suddenly gone. The camera then jumps back to the previous position where he had the tool, but it's also gone in that frame. He's now just having his arms crossed.
Answer: He was taking the labels off the bottles to make fake checks, using the logos as this is the one thing that he could not create on the checks. The MICR printer was only used to print the routing and account numbers and the emboss the checks.