its not uncommon at all for diesel engines to have oil leaks... ever notice at rest areas how the Semi-truck parking spots are completely covered in oil wheras the car spots are usually pretty clean? as long as you arent gushing it out and as long as its not getting into dangerous areas like severely hitting the exhaust around the turbo, it probably wont hurt anything..
I am a firm believe in Rotella T oil... I run it in my DT-360 and will run it in the new bus too.. my DT-360 sometimes leaves a few drops of oil on the ground, other times not.. its wierd..
my new bus left a couple drops of oil on the ground the first time I drove it from the lot to the hotel.. but on its 1100 mile trek to florida i didnt notice any oil on the ground.. so that one is intermittent..
and always be in the habit of checking your oil often... esp until you learn how much your bus uses..
change it, start fresh, drive it around and check it every day.. if on a road trip stop and check it every 100 miles and learn how it uses it.. nothing worse you can do to a diesel engine than to run it down low on oil... your oil Pressure gauge is not an oil level indicator.. if the gauge starts going down due to sucking air you are trashing the bearings.. (yeah its normal for the gauge to drop with the RPM's of the engine)...