Stumped

I swear this was discussed amongst the women's BQ attempt group but it's all a blur to me as far as what the consensus was. I'm looking at the schedule for four weeks to goal marathon and can't figure out where their math is coming from. The week is supposed to look like this (and I run my week starting on Sunday, not Monday as Advanced Marathoning formats the training schedules):

Sun-rest or XT
Mon-VO2 Max-8 miles w/5 x 600m @5K race pace, jog 90 seconds between
Tues-Medium Long Run-11 miles
Wed-rest or XT
Thur-Recovery + Speed- 4 mi w/6 x 100 meter strides
Fri-8 to 15K tuneup race (will actually do this Saturday, and move the long run to Sunday this once)
Sat (my Sunday)-Long Run-17 miles.

Pfitz says this is a weekly mileage of 50. If I take out the race, I get 40 miles, then depending on the race distance I get a maximum possible 49.3 miles. Maybe I shouldn't split hairs over it, but I am. Anyone have a clue? I don't this morning.

So my kids' naptime will be spent on that 8 mile run. Looking forward to getting it out of the way early so I can get my butt kicked at adult jazz. It's sad-I really thought I was in pretty good overall shape but that class kicked my butt when I tried it out last week. Guess that means I need to attend it more often.