Am I able to rearrange the Disc #s

[ddouglass]

Where are you looking that they are out of order? Search or the dropdown BookID on the main page?
What I did when we converted over to Hoster was to import them in the order they were in my books. Ours were numbered the same way as yours.
By importing them in the same order then the new BookIDs corresponded correctly to our books.
I think your sort problem is because you only used 2 digits for the first 99 (ie. 01, 02, 03,...) which combined in the list with 3 digit numbers (ie. 100, 101, 102,...) will not sort correctly. This is a common problem with Microsoft's sorter. If you were to delete those first 99 from Hoster, rename the folders with 001, etc. then that should fix it.