I had my best running on 5-6 miles twice a day. One long run a week of about 15 miles. This worked better for me than longer singles. I don't think that one program is "better" than the other intrinsically, but instead it depends on your recovery capacity (which in turn depends on a lot of other factors, like prior training.)
For me, two small stimuli a day was better for my training development than one large stimulus -- but I struggled through my whole career with recovery from hard efforts and had a tendency to overtrain easily.
At any rate, it's a solid plan, and worth seeing whether it bears fruit. The plan that works with your life and allows you to get your training in stress free is likely better than the plan that has you trying to reorganize your life to get your training in.