The actual pinch points on the side appear to be very small. There is maybe a 1 inch gap between the camera and the power on my Lumia 920. I do agree that the 928 looks to have a higher camera button than the 920/925, but the grip pad on the CR200 appear to only be maybe 0.5 inches, so it looks like it will fit the gap on all the phones.
ALTHOUGH! For what it is worth...the Lumia 928 is NOT listed as a recommended phone, BUT, the CR-200 is not "available" in the US and the Lumia 928 is not available World Wide...so they aren't going to say they are compatible if you can't buy both in 1 country.
Nokia Wireless Charging Car Holder Overview - Nokia