Howdy, and thank you for your continued aid in helping to improve Mythbuntu by taking the time to open this ticket! I am marking this as confirmed since it seems to contain enough information for the maintainers to work with. Just to make sure I'm understanding clearly:
1. You are trying to use mytharchive for files which you imported (mythvideo files), correct?
2. The estimated file size is sometimes different each time you run mytharchive for the same file (one time it was huge TB's, other time it was 16GB), correct?
BTW, trunk22304 is available. It contains a number of theme refinements and misc bug fixes. And, no you have not made a mistake. The last entry (22101) shows a previous version that you had installed on your system. You are running the one with *** next to it, 22167.