I also want to say that four, 10-minute flights is pushing the limits in my book.

Even though you say the servos worked after it was "on" all night, I'm guessing that you turned it off for a while first? This would give the batteries a chance to build up a little charge on their own, not much, but very possibly enough to let you move the servos around for a few seconds.

If you don't have a battery checker, use the 3-flight rule - Get 3 flights and re-charge.