Hi,
I have used Castrol Racing 1 in my previous SV (basically same engine as my DL, 46,000 miles) and found that it used oil. Once I switched back to Castrol 1 (part synthetic) oil consumption dropped to nil.
I am not sure what my dealer put into my new DL, but will ask at the 7,500 mile service. Once out of warranty I will be servicing the DL.