Hi Steve,
I think you'd be trading one explanation for another, since the addition of a new department would cause all the account ranges that include the new department to "disappear" when the manager opened their financial statements until SYS added them all back.
Another approach would be to display a message on drill down or Expand of "RangeDept" with something to the effect that:
Some department details are not displayed due to security restrictions. Contact user "SYS" to verify the display.
Perhaps there is also some tool we could provide for SYS which would make it easy (easier) to update the ranges and individual departments in user security.