I can recommend a small independently produced macro for managing (native)
flac tags - it doesn't do ID3 tags though. It's called Exceltagger and is
just a macro plugin for Excel. It was written by an enthusiast who uses/used
the online moniker of Willy Hoops but his website seems to have disappeared.
However, it's only 348Kb so I can easily email it to you if you want to try
it. I tried attaching it to this posting but that doesn't appear to work.
I've used the software extensively. It's super simple and it works well.