Is the oil the same for the variable and fixed servicing?

On a petrol, yes.

 

On a diesel, no.

Doesnt it depend on age of the vehicle? I thought they all the newer ones that is (petrol and diesel) on both service intervals use the 504.00 / 507.00?

Modern diesels require the long life oil (VW 507.00) whether on fixed or variable service intervals due to the specific requirements of DPF's (Diesel Particulate Filters).

 

Older diesels without DPF's can use a lower grade of oil if on fixed service intervals, however most use VW 507.00 regardless due to the small difference in cost.

 

Petrols on fixed intervals can also use a slightly lower grade of oil if desired.

Silver above is spot on.