Short Bus Drive

Looking at a FAA interpretation of these...

"...the pilot who is under the hood may log PIC time for that flight time in which he is the sole manipulator of the controls of the aircraft, provided he is rated for that aircraft. The appropriately rated safety pilot may concurrently log as second in command (SIC) that time during which he is acting as safety pilot.
The two pilots may, however, agree prior to initiating the flight that the safety pilot will be the PIC responsible for the operation and safety of the aircraft during the flight. If this is done, then the safety pilot may log all the flight time as PIC time in accordance with FAR 1.1 and the pilot under the hood may log, concurrently, all of the flight time during which he is the sole manipulator of the controls as PIC time in accordance with FAR 61.51(c)(2)(i)."

ALSO, in another to a person's questions:
"Approval for single pilot operations with use of an operative approved autopilot system under FAR 135.105 gives an operator an additional option in the conduct of operations. It does not mandate that all future flights be conducted in that manner. The operator can elect to fly trips with two pilots, as is otherwise required for flight in IFR conditions under FAR 135.101, using the second in command instead of the autopilot.
Your second question asks if, under the circumstances given above, the SIC can log time as SIC when the designated pilot in command is flying the aircraft. The answer is yes, as long as the certificate holder is using the SIC as a crewmember instead of exercising the autopilot authorization.In other words, the certificate holder elects not to conduct an IFR flight using the single pilot with a functioning autopilot option, but rather conducts an IFR flight using two qualified pilots.The two pilots are then "required by the regulations under which the flight is conducted", FAR 61.51(c)(3), and the assumption is that the second pilot (SIC) will function as a required crewmember, and SIC time may validly be logged. "

That person can even log (not ACT AS) PIC...
"If a pilot is designated as PIC for a flight by the certificate holder, as required by FAR 135.109, that person is pilot in command for the entire flight, no matter who is actually manipulating the controls of the aircraft, because that pilot is responsible for the safety and operation of the aircraft....a multiengine airplane flown under Part 135 by two pilots can have both pilots logging time as pilot in command when the appropriately rated second in command is manipulating the controls.
Note the "appropriately rated" part, and not ACTING as PIC.

Most airlines ask for PIC time in which you "signed for the aircraft" though, not "logged" it