The peril of getting your wish granted by a very exact genie
The brutal truth of outsourcing is that you will get exactly what you specified in the contract and nothing more. Everything else carries a fee and unless you have robust discipline and have planned really well (which few organisations do, especially in the first year) you will frequently find yourself dipping into contingency money just to carry on normal operations.
The reason is that same as why when requiring people to keep timesheets you often experience productivity drops; there were all those little extras people were doing. Someone who was staying on that extra half hour suddenly doesn't when watching the clock. Sadly this is a lesson which is mostly taught by experience.