I bought a used 06 E320 CDI with 19,000 miles on it back in January that was serviced just prior to me purchasing. It included an oil and filter change. I have only driven the car 5,000 miles since but I noticed when I started the car today that a schedule "C" service was due in 23 days. The owners manual indicates service A through H may display but provides no indication as what type of service is to be performed. Is there any published information on what specific service is needed as it relates to each letter that might display?