Yes. That sounds reasonable. Most decent garages use a guide publication which stipulates the length of time such jobs should take. That way they all end up singing off the same sheet so to speak. I recently changed a spring on the Lad's Xsara, which is a similar job, but less involved than the CMax, which also requires removal of the wipers, scuttle panel etc, to get access to the mounting. If everything had gone well with that job, it would have taken about an hour, but there was the inevitable seized bolt which slowed things down. The joys of older cars!!!
2008 2.0 TDCi Zetec