So I looked up the 10k from last fall to be exact I was wrong it was actually 41:44 and I did have HM PR in 70+ degrees at 1h40:07 but same theme applies.
Mostly seems like work up to try to get to 50-60 + mpw with quality work and results will translate better. Also thought that maybe those equivalancy calcs aren't perfect and maybe just geared towards shorter races. my weight is 147-150, at 5'9'', has crept up a little last 5 years, PR marathon 2018, 3:52 although on beginner plan less miles (27 mpw) weight was probably 142-145.
Even tho I was 35 mpw this last marrathon and ran 4h4 min many weeks were 40 mpw mid 40's. So wanted to make that distinction 35 mpw avg vs peak. and 50-60 mpw that's avg right (as will inevitably probably peak with 60+ weeks).
Just have questions whether to even pursue marathon - might be cooler to try to run sub 40 min 10k rather than bump up mileage only to have further disappointment.
One other note maybe not applicable but I did run a marathon once on NO training 10-15 mpw with one long run 13 mi in previous 4 months and ran 4h 14 min. So I guess what I'm getting at is since I ran 35 mpw last block and still sucked, what if I run 60 mpw and run 3:58 lol hence initial question maybe times just don't translate?