That's about as good as it gets, out of the box. A very tight projector, with only only 109K difference between the warmest and coolest settings.
The JVC's output is slightly cooler (about 200K - 250K higher) when the lamp is in low power mode.
As a side note, I normally leave a projector on, for about 30 minutes before beginning measurements, as I did when I first measured the RS2. A couple days later, I was rechecking some numbers, and was surprised to find that the same setup that generated, the 100IRE numbers above, measured about 300K higher, the second time around. Then I realized that I started the new measurement after the projector was only on about 5 minutes. Sure enough, I left the projector alone for a while, and came back, maybe 25 minutes later, and the numbers were again very close to the first measurements. The moral of the story? The color temperature of this projector (and no doubt every other one), changes a small, but significant amount over the first 30 minutes. (It likely continues to change, but only slightly). To verify that, I remeasured again, after about another 15 minutes, and the color temperature only shifted by about 20-30K.