UAV speed

I made the update to 2.6.3 version. Now the  UAV does not decrease depending on overlap and height. For overlap 80% and height 104 m, it should be 10.4 m / s and it's all 15 (phantom 3 advanced). There is no problem with version 2.6.2. From what I saw, in this case the speed begins to drop from 60m. Thank you