Hi Evan, I followed up with Cameratek with regard to the quotation you received.
When a lens is serviced/cleaned, the lens is stripped-down. The image stabilizer and lens elements are removed and cleaned. After cleaning, The image stabilizer and lens elements are reassembled. Two technicians then re-calibrate the lens manually. After the manual calibration the lens is connected to a computer for final calibration. This process can take up to a day to complete.
If you have any further questions you are welcome to contact me directly