HTC CEO Peter Chou has come out swinging against allegations that HTC is paying "$6-8 per handset" in royalties to Apple, calling the estimates "outrageous." Of course, those estimate were indeed just estimates, and they were also commented upon by HTC insiders at the time as being a little on the high side.
So, what do we take from Mr. Chou's statement? HTC is probably paying a royalty, but a $6-8 royalty (that's about 1-1.5% on a $600-800 smartphone)? Probably not. Who knows, it could be $3-5! Which, admittedly, would mean slashing the financial impact of the deal on HTC's coffers by up to half. But still, this is a small royalty to start with, especially given that Apple sought to arrange a patent licensing deal with Samsung back in 2010 at $30 per phone.
Patent royalties, by their nature, are usually assessed on a percentage of MSRP basis, with 1-2.5% being an extremely common range in the tech world. And let's not forget, not every smartphone HTC sells has a $600+ pricetag. In fact, probably well over half of HTC's smartphone sales are low-end and mid-range devices, meaning that the $6-8 number may not actually be wrong for a phone like, say, the One X+, or the DROID DNA. But phones like the One VX, Desire X, and One V may undercut that number through volume of sales.
Regardless, the terms of this settlement will likely remain out of the public eye for the foreseeable future (Samsung's request for them in its trial against Apple will be under seal and heavily redacted, most likely, if it's even granted), so we may not learn exactly how this deal went down until well after no one really cares anymore.