There is a scene in Star Trek II: The Wrath Of Khan that takes place in the transporter room of Regula One where Kirk (in the away team) speaks to the Enterprise bridge. Khan is eavesdropping on this conversation, a fact which Spock either knows or suspects, because the conversation happens in code:
SPOCK: Admiral, if we go by the book, like Lieutenant Saavik, hours could seem like days.
KIRK: I read you, Captain. Let's have it.
SPOCK: The situation is grave, Admiral. We won't have main power for six days at least. Auxiliary power has temporarily failed, but maybe we can restore that in two days. By the book, Admiral.
So Spock would appear to be saying that main power will be out for six hours and auxiliary power for two hours.
Kirk then gives this order:
KIRK: Captain Spock, if you do not hear from us within one hour your orders are to restore what power you can, take the Enterprise to the nearest Star Base and alert Starfleet command when you are out of jamming range.
But, later on, there is this exchange:
KIRK: Kirk to Spock. It's been two hours, are you ready?
SPOCK: Right on schedule, Admiral. Give us your coordinates and we'll beam you aboard.
My question is, what did Enterprise do during those two hours? Kirk orders Enterprise to leave after one hour, but two hours later she is still in orbit. Did she leave and return? If she did leave, how did Spock know to return, given that Kirk did not say anything about two hours? Two hours does not sound like enough time to go to a Starbase, and back again. Is Kirk's message in code, and if so, is it in the same code that Spock used?