There is no general duration_per_duration unit group

[rjyounes]

The only unit group we have for duration-per-duration units is gistd:_UnitGroup_labor_consumption_rate. This is really an aspect rather than a unit group. Shouldn't we have:

gistd:_Aspect_labor_consumption_rate gist:hasUnitGroup gistd:_UnitGroup_duration_per_duration .
gistd:_UnitOfMeasure_hour_per_week gist:isMemberOf gistd:_UnitGroup_duration_per_duration .

Seems like we should be able to have another aspect for, say, PTO accrual rate, that connects to the same unit group. The way I think of this is that an aspect is a feature being measured, and a unit group is a collection of units that measure the same one or more aspects, but the unit group shouldn't build in the meaning of the aspect itself. That is, it should be kept general enough to cover multiple aspects that can be measured with the same units. This may not work in all cases, but it would work here.