Advice & Experiences on RW's Ultimate Marathon Schedule: Sub 3:15

After having run 3 marathons to date with varying amounts of success, I've decided to run another in October and follow Runners World's Ultimate Marathon Schedule for Sub 3:15. My first marathon I ran in 2015 with a time of 3:34:49, my second in April 2016 in 3:12:03 and then my third in November 2016 in 3:23:13.

Has anyone followed this training plan before? I ask as I've looked at the paces for the scheduled runs on a Monday, Wednesday and the LSR on Sunday and they seem very slow to me. For example, the Monday's would have me running at a pace of 8:45 min/mile and the Wednesday runs are on average about 8 min/mile. Normally on an average paced run I would go out and do 7:45's, hence why I'm questioning whether the training pace is too slow.

If anyone has followed this plan before it would be good to hear of your experiences with it and if running slower whilst training actually was successful!