I would go with Delo as the cost is low, the TBN is high and the additive package is stronger. It's meant for fleet service. I would change the oil and filter out at the same time. I would also start with the 2T oil in the fuel it will reduce maintenance cost and allow you to run your oil longer because it helps your burn excess diesel.

Now this is how you save your company a bunch of money, Run the oil 12000klm and send of a sample of the oil for testing at one of the labs I posted and make sure you get a TBN. This will tell you just how long you can run this oil and filter with no guess work. Oil test is less than 1000P for most places and can save you 10000's of dollars in oil change cost. Top1 will also easily go that same distance with these filters since it's group III oil.

There is no reason Delo can not go to 12000klm that's actually a low estimate on that oil. Remember the reason to use Baldwin or Fleetguard filters is to extend oil life and reduce cost. 150000kml is not a unreasonable oil change interval on that engine with a Baldwin since it holds about 4 times more dirt than a standard over the counter filter and it filters down to 12 microns * 50%.

Please sir, keep up updated. It's good to know people can start saving some money with all the input from members on this forum.