Comment #4 on issue 2820 by [email protected]: Tab staff repeat sign http://code.google.com/p/lilypond/issues/detail?id=2820
It probably depends on whether the minimum space is required in order not to leave the staff lines altogether. Without outer staff lines to contain them, I am not sure the dots would not be better placed like you did.
On the other hand, with a single staff line you need to put the dots outside anyway, so it might not be all that bad for double staff lines. Perhaps we should avoid inventing too many different rules for special cases that are rare to occur in practice. TabStaff and plainchant _are_ things we want to work out of the box.
