Typically advancing the fuel delivery of a diesel will increase combustion pressure which results in an increased load on pistons, rods, bearings... "pinging".

At the same time it generally will increase economy, lower exhaust temperature at the expense of a higher NOx emission. However, the HC will decrease with earlier injection. Smoke may increase at peak torque rpm and decrease at idle.

The specific time of delivery is also based on the pop pressure of the injectors as well as fuel viscosity. So, the drip method of setting the injection timing is meaningless if the pop pressure is not within spec.

I really wouldn't worry about it too much if it runs good and the timing chain and tensioner/rail is in good shape. I read too many storys about new chains letting loose. MB allows for quite a bit of enlongation by the use of offset woodruff keys to restore the valve timing.

BTW, I'd like to advance the cam to lower the peak torque rpm. I wonder how many degrees is too far???