Vacation Rule - Approval Hierarchy

 Has anyone had any problems with approval hierarchies on expense reports due to vacation rules?

For example, Employee A reports to Supervisor B who reports to Manager C. Supervisor B has a $250 signing limit and Manager C has a $500 signing limit. Employee A files an expense report for $350. After Supervisor B approves the expense report, it will go to Manager C for approval (since the expense report was over the $250 signing limit that Supervisor B has). However, if Manager C creates a vacation rule delegating approval back to Supervisor B...Supervisor B now will have signing authority to approve for the same amount as Manager C.