The reality is that they don't need that much service.
Read any manual from any shock company and literally NO ONE does the recommend service.
http://www.cannondale.com/asset/iu_..._ultra_dlr_dl_owners_manual_supplement_en.pdf
Maintenance
Maintenance of your fork is important to your safety and to the useful life of the fork. Frequent inspection by you and regular professional service by your Cannondale Dealer can help ensure years of safe/trouble-free operation.
WHAT TO DO
HOW OFTEN
WHO?
OVERALL FORK INSPECTION
Clean and visually inspect entire fork for cracks or damage. Things that can indicate a serious problem:
(1) Unusual “klunking” or knocking noises
(2) changes in travel
(3) Over-extended or compressed boot
(4) Changes in the way the fork
has been working
(5) Loss of adjustments features.
(6). Sudden air loss or leaking fluid.
If you experience any of the above conditions, have the fork inspected by your Cannondale Dealer before riding it.
Before and After Each Ride
YOU
BOOT INSPECT
Before and After Each Ride
YOU
UNDER BOOT GREASE RENEWAL
Every 2 months
DEALER
BOOT REPLACE (Annual renewal suggested)
As Needed
DEALER
INSPECTION REBUILD
Inspect and disassembly of telescope and races, bearings, main telescope parts, damper cartridge, fluids, etc.
RACE: Every 6 months
NORMAL: Annually
DEALER