I have that set to 5.5v and power goes directly from it to the Rc Rx, which has a 5V rail and a ground rail, these rails go directly to the servos power.
Many IC's have a 5.5V max Vcc power specification. The servos motors, if they have suppression diodes, will clamp the spikes to around 6.2V. The more motors running and the higher the speed, the more 6.2V "spikes" there could be. Its best to set the supply to 4.5-5V. Better yet, separate power sources for the electronics and servo motors would be an improvement.