My guess is that the oil cooler is working but the engine electronics will still have the engine run between the 210 and 300 markers.
The other part to my guess is that you'll also need some sort of DME tuning or new thermostat to get the engine oil to actually run cooler.
2015 F34 328iX GT Glacier Silver
2011 E90 M3 Monte Carlo Blue
2004 E46 M3 Imola Red