You don't know what it will cost or if you need it. You've also said that the reason you can't give the PBO the information it has asked for and is lawfully entitled to receive is that you are concerned about the individual workers in the public service.
If you're going to get to your goal through people leaving voluntarily, there are no individuals who will be forced out. Furthermore, they're self-selecting. There is no privacy issue here. There is no individual whose either privacy or information would be out early.
Why don't you just do what you're required to under the Parliament of Canada Act and give the PBO the information that it's asked for so that parliamentarians have access to the PBO's advice before we vote on these supplementary estimates?