I can't think of anything more irritating than phone numbers during TV commercials ! I don't know how they manage to do it, but they always succeed to find the most creepy voice as possible. Sorry, but it scares me to the extreme, more than any willingness to call ! They always sound like some kind of serial killer or pervert *LOL*.
But other times, I feel some pity for these persons who are hired to just tell phone numbers. Pay attention, and you'll notice that some of them sound totally demotivated, depressed, and bored ! I guess I would if I had to spend my days pronouncing phone number!
So please, find other and more appealing methods to get the attention of people, and make them call or contact you. I am sure there are plenty of creative guys all around, who can find alternative solutions, and make your commercials pop out of the others.
Really, who has the time to listen and note the phone number? It's not because it's said loud, that it will make it easier to memorize and write it down ! So what's the point?