Apple seems to want to set the rates themselves. That's not how it works. A patent holder or judge/arbitrator gets to do that.
Now, consider this: the last major cell phone ban from the ITC was over Qualcomm chips that it said infringed on a Broadcom patent. The royalty rate for that license was set at $6 per device (!).
Edit: interestingly, in that Broadcom injunction, neither the President nor appeals reversed the ITC decision, even though it banned almost every CDMA phone being imported at the time. Since Qualcomm initially appealed and refused to pay, Verizon itself ended up paying Broadcom $6 per phone just to keep from running out of stock.
2.5% of Apples top iPhone comes to $21, or almost 4 times higher than $6
Given the difference between the top/bottom phones is the amount of RAM which has nothing to do with Samsung's Patent and given much of the value of the iPhones is IOS Samsung clearly does not deserve a percentage of the finished product. This tactic would lead to another absurdity of selling the phone to $1 and IOS for $800, giving Samsung 2.5cents per unit (hell give the phone away with $1 so Samsung OWES apple 2.5c).
Samsung in entitled to payment for their IP, however when you can buy a complete phone for the same cost as what they are demanding from Apple as royalty then Samsung is simply being greedy and that is clearly NOT FRAND