Apple Computer Inc’s strategy to build market share with its new low-cost Macintosh Classic is proving so much more successful than the company expected that Apple’s margins are falling faster than the company planned, and the good news on the sales front is being taken as bad news on Wall Street, where Apple’s share price tumbled $7.75 to $47.25 – they were $73.25 in mid-April – after the company warned that its gross profit margin would slip because of changes in currency exchange rates and because of the rush to buy Classics – shipments soared 85% last quarter and continued to grow in the first month of this quarter, which means that profits are likely to be down.