I just changed the 12 volt battery on my '13 C-Max for the first time. It was a little bit of a challenge due to no mechanical latch on the back hatch door, but it worked out. The dealer has suggested that I bring the car in to have the computer reset (1/2 hour labor). I understand that some high end cars do require that the onboard computers be synced with an individual battery, but is that really necessary on a C-Max?  What are the risk if I don't do that?