I quit looking for the variable and use the height and width values to determine the via type.
~>cutHeight and ~>cutWidth
In reply to psill000:
It doesn't store the cutClass - for example, the edit properties form uses a lookup based on the parameters of the via and sees if it matches the cutClass definitions.
There is a section in the documentation entitled Accessing cutClass information using SKILL - you should be able to search for this in cdnshelp - although you'll have to do the lookup yourself if you want to find the match.