More inadequacy... and Revit Unit Quirks

It's sad - Jeremy Tammik has blogged more about me than I have this month.
(His latest is an outgrowth of an Autodesk Developer Network question I submitted a couple of weeks ago - about why, in the Revit API, asking for the "SiteAngle" dimesion format data causes an exception - along with a variety of other interest

The short version:
Revit will throw an Exception if:

• You are running one "vertical" (i.e. Revit Architecture) and you ask for a dimension type which is ONLY in another vertical (i.e. Revit MEP).
• You ask for one of the four unit types which are un-modifiable (i.e. SiteAngle, SheetLength, etc).

Not very friendly, but at least now you know :).