When I was in Uni I had a similar experience. I never collected enough data to really show a conclusive relationship and obviously it was possible my writing improved around the same time that I switched.. but it was still something that I noticed.

One of my theories was that professors expected rushed papers to have poor or missing formatting, but my rushed papers wouldn't. The formatting was therefore sending a signal to the professor saying "He didn't write this in the morning, so give him the benefit of the doubt." I never considered that the typeface that I was using could have been involved.