Does anyone have a lisp routine that will change the units of a dimension
from metric to english units while converting the specified tolerance?

I can use dimension styles, however, switching between them results
in a lost tolerance. See example:

I have 100+/-2

changing the dimstyle I get

3.93 without a tolerance.

Is it possible to get 3.93 +/-0.08?

Are there too many variables that the routine would have to manipulate?