@mdboom - sorry to get back to this rather late.  As currently written, the expression *ignores* the scale of the unit, so one should either do what I propose, or
```
represents = CompositeUnit(represents.value, [represents.unit], [1])
```
The latter would indeed be consistent with the current treatment of `s`, so we can certainly change to that if you think it is better (I do think the two should be consistent!). Let me know if you would like me to adjust the PR.