@JessicaLynn - I see what you're saying, but I think sometimes companies get a little crazy with their fraud-reduction measures. In a process like invoice reconciliation, it may actually make more sense to have one person handle most of it.
I've found that when tasks are split up like that, if all the parties involved don't communicate, it never works well. I guess if all parties involved are good communicators it would work. But if not, I can see a lot of potential problems.