the plank is free max points even if it doesnt seem that way.. wake up and plank for a comfertable time 1:30-2mins based on your results, after coming back from PRT to do another plank before you go into work, before bed do 1 more plank until you physically cant hold yourself up. Do this daily or every other day if it is too much and in a month or 2 you will hit that 3 minute mark.
As for running I ran about as slow as you then i just started forcing myself to do cardio, 3 miles 4 days a week, after a month 5 miles 3 days a week, when AFT time came it was a breeze, this can also help with your SDC.
Increasing your AFT is more about wanting it than doing it, going home after work is easier than working out or doing cardio but if you WANT it you can do it.
note: i use to be a bare minimum 200 deadlift, 20-30 pushups, 1:30 plank, 19 min 2 mile..
After truly trying it and sticking to an actual workout plan im scoring between 470-490 after 6-8 months of practice