Personally, I disagree. A local number is a clear signal that the business is based in said location, and covers said location. If you're using a local number, for national/international business, I think it's sending mixed signals to Google & the users. Same the other way round, not quite as bad, but I'd still prefer to use a local number for local business. Should be noted to anybody reading this, I haven't done any tests to prove my theory right, so my thoughts are opinion and not a fact.