Changing Transmission Fluid - 2004 X3

[bkmcgraw]

I recently purchased a pre-owned 2004 X3 with 60K miles on it. Conventional wisdom tells me to change the tranny and differential/transfer case fluids--normally at 30K mile intervals. The BMW tech told me during the Inspection II just completed that I don't need to change these until 100,000 miles. WHAT!!!!????

Synthetic or not these fluids need to be changed, correct? I want to drive this vehicle for several years and this doesn't make any sense. Any advice? Is it imperative I use the synthetic fluids BMW recommends or will conventional do (if I change every 30K miles)?