I believe you did this at 1,200 miles? Changing the oil was a waste of resources. For example, the differential fill is nearly good forever which was implied by no drain plug. You mentioned the oil looked dirty, but this was due to an additive added to help with the break in of the gears.
I don't know what the BMW service interval is for the transmission, but I figure a reasonable number might be 50K miles. In fact, that number Redline tossed out to me regarding their own products. I'm assuming that BMW thinks their transmission deserve lubricants as good as Redline's?
There seems to implied in these threads that BMW is a party to some conspiracy to extend service intervals to reduce their costs for their maintenance programs. Nothing could be further from the truth.
Lubricant technology has progressed along with other automotive advances to provide longer service intervals. Motor oil doesn't need to be changed at 3,000 miles. You might notice that the BMW crankcase capacity is 7 qts, and that along with synthetic oils have made possible at least 10K mile intervals for engine oil.
Another example is some Mazda's have a 4.5 qt capacity with an interval of 7.5K miles.
