Work out total laundry time including sorting, washing, drying and folding.
Laundry time is the machine time plus your own time. Each load occupies the washer for its cycle and then the dryer for its cycle, so machine time is loads x (wash + dry). Sorting and folding is separate hands-on time that you can overlap with a running machine, which is why the two figures are reported apart: the total tells you when the last load is finished, the hands-on figure tells you how much of that you actually have to be present for.
Machine time
machine minutes = loads x (wash cycle + dryer cycle)
Total time
total = machine minutes + loads x sorting and folding minutes
Yes. With one washer and one dryer you can wash load two while load one dries, which in practice removes most of the washer time from the critical path. This figure is the sequential worst case, so treat it as the upper bound.
Because they cost you differently. Machine time runs unattended, so only the hands-on figure competes with everything else you have to do.