Merc care plan, recommended or not?

Hi, i have a 57 reg E220 diesel auto with 92,500 miles, Merc FSH and my dash is reporting Service C (which apparently is only a small service ie oil and filter change etc) in 26 days. Have checked out Merc care plan as want to keep Merc FSH and this will cost me about £69 for 12 months and cover me for next 3 services at Merc garage.
Just wanted to get advice and info on this and whether its worth taking out? Any advice would be greatly appreciated. Thanks