That's weird. DannyGT, if I remember correctly, is running 9.5" +22 in the front with a 265 tire. He said that with skinnier tires, like a 255, he'd have better clearance.
The +15 is only 7mm different, so I'd assume that such a small difference would be manageable in the grand scheme of things. Nothing a skinnier tire or some more negative camber in the front can't solve.