I have just charged a customer R 3333.16 for a 20 000 Km on his 2105 R1200GS LC (K50)
This included, oil (I only use Liqui Moly - which is more expensive but the best in the industry) Final drive oil, brake fluid, filters, plugs, labour & engine flush which everybody forgets how important this is..............
NB. the customer opted for a performance Air Filter (washable instead of replacement) which was R 961.22 which makes the cost of the service more realistic at R 2371.94
Also consider the big killer in this service is the sodding spark plugs - they are a whopping R 776.20 for four plugs - take that off it comes down to R 1600.00 - more realistic again.
I have just done the 30 000 Km service on my own R1200GS LC (K50) and to be honest I pulled the plugs, inspected them and they were seriously not showing any signs of wear or degradation at all - I cleaned them and put them back - my bike is running just peachy! They weren't changed at 20 000 Kms either - maybe it's just that ex-Rhodie in me........

With servicing customers bikes, I go by the book.
Just a point to note about the Liqui Moly Oils
When I got my bike it had 9 000Kms on it....I first noticed that it ran rather hot? Steve at Northside said it was within spec but once I had changed the oil to Liqui Moly it went from running around at 92*C to 84-86*C and a bit quieter (it's a 2015)
I rode Bavarians R1200GS LC in the Economy Run two years ago and my quest was to be the first Duallie over 1000cc to go under 4.0Lts/100Km and I couldn't get there until I changed the oil to Liqui Moly and I won my class in the event at 3.971 Lt/100Kms
Top grade oil makes all the difference!