For me it works correctly. I think the problem might be somewhere else... Are you sure that the modification times of the files are older than one hour?
I figured out what's the problem. Besides Build Mode BLITZ should also be enabled in Output Mode. Unfortunately, this will create a separate GCC.Blitz.Gui.Shared configuration, which is not created in case of Debug Mode.
Otherwise it works pretty well.
Overhead in case of TheIDE is ~12k and ~40k in case of a small console application. This is acceptable.