Your asumption is correct, when giving a thelepone number in Spanish, we normally separate the Zone Code as a sole number then state the rest of the numbers in pairs. Sometimes there are numbers in which the Zone Code, we call it "Lada" by the way, and the phone number make it to ten numbers for example: 22 99 34 35 36 then you can say the number all in pairs: in this case it would be:
veintidos, noventa y nueve, treinta y cuatro, treinta y cinco, treinta y seis.
So to sum up, your question and answer are correct.