First, what is air speed? Air speed is the delta between ground speed and wind speed. On a perfectly calm day air speed is equal to ground speed. With a tailwind the air speed is less than the ground speed and the opposite is true with a headwind. This seems counterintuitive, but is important because it reflects how much energy the drone is having to expend. This is another reason why it's best to fly parallel with the wind direction. The energy expense is more even than if it was a crosswind and the drone is compensating for that the entire flight.
With DroneDeploy the system sets your speed to achieve the overlaps, but does not take into account the wind so if you set 70% frontlap and are in a headwind you will get more than 70% so you can manipulate that if you want. Sidelap is sidelap regardless.
As a general rule, if the drone can't sustain 10mph I don't try to map. I may still take pictures and video, but wouldn't stake my reputation on the accuracy or feel it necessary to put that much stress on it.