I spoke to them and they have charged me 3 hours labour for the service and 1 hour to rectify the "fault". As it turns out, and in my defense, the set up for water separator alarm on a "G3" smartcraft engine is simply a case of plugging the sensor in to the harness. There is no need to modify any settings. What they have done is clear the tank 2 calibration. The tech had a go, as I did, at setting it up as per earlier systems, but then called Barrus to confirm this was not required. I can deal with the time doing this, but 3 hours for a 20 hour/3 month service still seems a lot.