I was a bit confused about why it would matter, but then realized I brush, then floss, then use a fluoride rinse, which isn't really addressed by the study. If you didn't use a rinse or a fluoride floss, presumably the toothpaste from brushing would be more likely to get into the areas between your teeth after flossing.
If you use a fluoride rinse or fluoride floss I'm not sure it would matter much, or brushing first might even be better, because it would remove material to make flossing more effective. Maybe?
