Reading over the Small Business Server 6.6 documentation I find that for
4.x and 5.x SBS servers I can migrate, but if I have a 6.0 server it says
to do an inplace upgrade first and then migrate. (copy of docs is below)

This is more work than I expected and I can't go back to the original
server in case the migration goes awry.

Is it really true. Does anyone know what the problem is with doing a
migration from a SBS 6.0 server to SBS 6.6? The Migration Wizard 8.0
documentation indicates that 6.0 IS a valid source server for a migration
to 6.5.