TextNodeElement.AnnotationScaleFactor

Is there a way to extract the AnnotationScaleFactor from a TextNodeElement.  I have found a method for getting the AnnotationScaleFactor from TextElements and DimensionElements, but TextNodeElements do not seem to directly have a property for AnnotationScaleFactor.  As I understand it TextNodes are a complex elements but I am not sure how to break out the sub-element properties.

Thanks for any suggestions.