Time for an update:
Yesterday I looked at the Panel schedules [which aren't on my copy] and they show 2000 warrs abd a 30 ano, 2 pole breaker. Thus the 10-2.
This morning I asked the super and he looked at the plumbers sheet and their plan is to use a 30 gallon cold water heater and feed all the sinks with that. This is design build, everything is co=ordinated.
The bad news for this thread is that we will never know exactly what was intended.
Thank you for your insights.
~Peter