Apologies for butting in,
Rory are you saying that the IDE will run Class Code if it comes across a variable that is defined in a Class Module? (I've never used a class in Excel, but think I know a little about the structure - could very well be completely wrong).
My experience with Non Class VBA (normal, easy stuff) is that the IDE only reports the current value of a variable as is held internally at the time the Break halts execution. It doesn't run the code to calculate new figures.