As you see even in trainings that are pace stimulus similar to the race pace 2 runners from the same performance they have different capacities to run that workouts. The same applies to what I see people to discuss often in this site: what´s the pace you may run aerobic runs. Since that less than 80% race effort that is an effort distant than race pace the physical needs are different for each one, then ther´s no a fix rule to run that easy runs (neither the lactic acid or mmol tests or heart rate can´t save the problem), the more with LT runs. Well, by this I don´t want to say that we need to train just to get your shoes used. Train may be considered an effort or that´s better to stay home and rest. This are also the reasons that to train for a mmol value (anaerobic threshold or whatever) that´s not accurate considering each one individual case.
In my opinion the lesson is – in efforts that re distant than the competition needs, different runners they often do not similar training results, but similar performers they also may have different answers to same training stimulus. This is also the reason that´s wrong (or impossible) to give personal advise without know the runner profile or out of the runner presence. That´s not effective to train by cook book or digest schedules.
Ps- One more comment. Both runner´s number 3 and 4 they did that 3X800m 3 times along the summer season and 2 times the 3X1000, but as i told you one for the runers were able to complte only 500m in the 3rd rep. of the 3X1000m check test isntad of the desired 3X1000m.