That's my point exactly. The Nottingham service has around 100min layover time and 200min travelling time per cycle. Taking one set out of the hourly service would give a total of 40min layover, a little tight but probably do-able if the timetable can be structured to split it evenly between the two termini and even better if a few minutes can be squeezed out of the journey time to add to the turnaround. One reason for the current arrangement is because it's the only off-peak service group operated with HSTs so it can't interwork with the other services - a uniform fleet allows interworking to balance out the turnaround times.
But in the context of the interim fleet post-HST they will have the following train permutations
Cl222: 4, 5, 7, 9, 10 car
Cl180: 5, 10 car
7 different possible formations
This is very different to the long term situation.
This falls to 2 once the new fleet arrives
My scepticism is whether this interim fleet of 31 trains with 4 different subtypes can provide the necessary capacity (reliably), when Abellio have been telling the world they need 33 trains of a single type. Especially since the 180s have such a woeful reputation.
I really hope MR grilled them on this.