You can actually refresh specific rows adjacent to frequently accessed ones by issuing ACT->Precharge command combos. Timed right it only comes into play during attacks (whether intentional or by coincidence) and therefore has little additional power usage.

Also that release note was for the Mac not the iPhone. They are less likely to apply that mitigation to the iPhone precisely because it would result in increased power consumption. They could however integrate the more advanced fix in the memory controller since they control the SoC. I would expect them to brag about it if they had.

Exactly, that is a beautiful mitigation - as long as you can upgrade the memory controller. I really hope vendors are doing this on all new chips!