i have a santro club 2003, i hv observed it has reduced some oil
define SOME OIL.
i drive normally at 140 km/h on cng on motorway and the car goes easily to 155-160 km/h on petrol.
high speed driving may result in oil reduction. Normal acceptable reduction range is upto 1 liter per 1000 km of drive. Keep topping it up as and when oil level is reduced, but do not overfill.
However, agar tassali na ho tau you better check for external and internal leakage before throwing money to workshops for mini or major overhauls.