Is it really necessary to oil change at 100 hrs these days.

[NorthUp]

Like I wrote, its all relative.
My 26'er takes about 5 litres , so I don't bother testing, the other boat I get to play with takes 2 x 80 litres, so the owner does...

 

[Marsupial]

Quite, they really should employ people who can read

see here

http://www.jcbvolkswagen.co.uk/Servicing/JCB-Service-Plans---New/

in fact the advice they give is not dissimilar from mine - there's nothing new under the sun