Only problem I see with this is, if she really wants to talk on the phone after 10 bad enough, she'll find a way.
Not trying to be a party-pooper or a parenting genius, but I am 17 and know the feeling of wanting to stay up late talking on the phone. Personally, the best thing i can recommend is to just try instilling the right values of going to bed at the right time and NOT staying up late talking on the phone. Most teens (myself included) don't really like this idea all too much, but after a few mornings of draggin' a** to school, we get the picture and actually WANT to go to bed earlier instead of staying up late talking.
Just my two cents. Best of luck on the Phone Radio time-locking
