The "official" way of pronouncing numbers was indeed changed for that reason (NB: That was back when there were still phone central operators and you were supposed to tell them the number) However - the "old" way ("two and forty") is alive and well, very much so by the oldest generation of course, but among much younger people too. Most people alive use both ways - for some stuff it's simply more natural or easier to say "fem-og-tredve" than "tretti-fem".