Hey Colleen -
Yeah, this could be just a semantics issue. One way to look at it is allowing a person X to act on my behalf includes delegating my authority to person Y.
Here is the scenario that actually have happened at my company. I am an approver. I go on vacation and delegate my authority to person X. Unexpectedly, the person X had to leave the country to attend a personal emergency. He delegates his authority to person Y. All my approval requests went to person X and sat in his queue until he got back, instead of getting forwarded to person Y.
So, maybe you right and the workaround is to delegate my authority to X, Y and Z assuming one of them would be available during my absence.
Thanks for the answer.