OK, and what would you do until the feature is implemented?
There threads that date back to 2006 or see e.g. this thread:
and that nothing has changed in the meantime.
So far, the philosophy is that tag data from different file type and tag types have to be accumulated in an internal field variable. After that accumulation, there is no way to trace back which data came from which tag version.
I am not too confident that a change of the basic handling will come very soon.