Are you saying the A models take longer to align the INS or that the C model does not require any time to align the INS?
In the INS / ALIGN Sub-Page we have the option for ground alignment (R3), or Inflt alignment (R5)
R3 - When first starting the aircraft and aligning it on the ground, GROUND will be selected by default. This results in a full gyrocompass alignment. The average ground alignment time is 5 minutes and is automatically started when the EGI switch is set to ON. The aircraft must not be moving for correct alignment.
R5 - If the INS alignment needs to be re-aligned while the aircraft is in flight or moving on the ground, this option is used. This alignment process uses current position and velocity measurements from the INS. Before starting an in flight alignment, EGI, STR PT and ANCHR should be deselected from the Navigation Mode Select Panel or select HARS. The EGI GPS will then be used to align the EGI INS. This process can take between 5 and 10 minutes.