Actually, it would be pretty significantly below average at most schools I'm familiar with. Most people who attend lectures do another handful of hours on top and the grand total is well over six hours/day. Those who don't attend lecture spend most of the time they would have been in lecture in the library and still do a handful of hours on top of that adding up to well over six hours/day. In college you could get by on a mere 6 hours (eg 10-4) of work and do well. Not so much in med school unless you are the exception. And if you are the exception (which I assume you are if you think this isn't a low figure, then you really shouldn't be giving advice to premeds, who are going to show up and get destroyed if they play this game). In general, the tried and true system for most med students is repetition, repetition, repetition. None of this once through the material garbage. Here's what many of us have found works -- You preread the lecture material the night before, you attend lecture (or read the lecture materials individually), you review what was covered in lecture that night, and then on the weekend, you review again, and do a once over through the material once again before the exam. So we are talking FIVE times through the material before the exam. And that's a lot of work compared to what most of us did in college, where a "once over through the material" or night before cramming actually worked fine.
Everybody is unique, and they have to find what works for them. But you are kidding yourself if you think that the AVERAGE med student doesn't have to work really hard -- substantially harder than in college, and a lot more than a mere 5-6 hours/day to get by. I agree that becoming efficient will be important during first year. Most people spend much of the year tweaking things until they have a system that works for them. But being more efficient isn't going to get you down to a handful of hours a day. It will shave a couple of hours off of a very full day.