Remember that while this increase is well needed and I am happy for it, its not as altruistic as it might sound.
By 2020, all stores should be converted to a full E2E process and therefore the most common denominator for pay is an N7, not an N3. Most of your TMs will be Flow TMs who can do SF/GE tasks throughout the day. This means that the base pay for them would be $11 + $2 (Shift Diff + Log Pay), or $13. So their plan to increase everyone to $15 (while an investment) is going to be 2 more bucks an hour over the next 2-3 years because the TMs expectations will be vastly different.
To me, this is them telling us how they are dealing with the change in expectations vs pay (for example, that SL currently has to do flow's work plus their own, but is paid like a normal SFTM)