The Fundamental Period is the basis aerobic phase, and you have given examples of runs lasting 30'-50' at a pace 1.3x- 1.4x slower per 100m of RP for 1500m.
So for 345 1500, the pace of these runs would be 19.5-21/100m or 315/k- 330/k.
For 32' 10k, the pace is 1.15-1.25x slower /100m...so pace is 340-344/ 1k or a little faster than 6min/mile.
These runs are around lactate threshold, and, other than incorporating long runs, and easy runs, are there different workouts than you incorporate into this period to enhance the pace of aerobic runs?