yep, then that makes sense. at 100 degrees and higher rpm's like that, the car is just going to want to run hotter. No fan on the planet is going to lower the temps better than 80mph air flow. However, you might want to analyze the air flow as it comes through the grill. Could it be getting channeled below, above or to the side of hte radiator? Adding some type of baffle to force more air through the radiator could really help during these high speed driving conditions.
That being said, if you can stay at 210 for indefinite amount of time at those speeds, you should be fine.