In a note to clients — as reported by “AppleInsider” (http://www.appleinsider.com) — BMO Capital analyst Keith Bachman said he expects Apple to post a “significant miss”for its fourth fiscal quarter of 2012 as Mac sales continue to be cannibalized by the company’s iPad tablet line. I have to disagree.

Despite raising sales estimates for both the iPhone and iPad, Bachman said the June quarter and upcoming final fiscal quarter of 2012 will be “challenging” for Apple as the tech company Apple could see an US$5.5 billion miss from the $38.5 billion consensus for the company’s fourth fiscal quarter ending in September if its third quarter performance is in line with the current $37.5 billion forecast, according to historical patterns and outlooks.

Bachman says his Mac sales estimate is expected to drop 1.6 million units over the same six quarter period. He dropped his Mac sales estimate from 18.65 million units to 18.22 million for 2012 and sees that decline carrying over into 2013 which slipped to 20.18 million from 21.38 million.

“Net, we are lowering our Mac forecast by 1.6 million units over the next six quarters,” Bachman says.”We think strong iPad demand is negatively affecting Mac sales, despite the recent MacBook refresh. For the next six Qs, we reduced our Mac sales by 40% of the increase in iPad sales.”

Yours Truly expects Mac sales to dip a bit in the just-ended June quarter because no new desktops or laptops were released, not due to any iPad cannibalization. Bachman says he expects said cannibalization to “continue.” As far as I can tell, there’s been no discernible decline in Mac sales due to the tablet, so there’s no cannibalization to continue.

New MacBook Pros — including the Retina display model — and MacBook Airs were announced at the Apple Worldwide Developer Conference on June 11. However, by the time they went on sale it was too late to have much impact on the June quarter. 

This fiscal quarter will be a different story. New laptop sales will move a significant number of new Mac units, especially if the rumored 13-inch Retina display MacBook Pro appears soon.

Over the next 6-12 months, look for a Retina display iMac and a seriously revamped Mac Pro. These will further fuel Mac sales.

My forecast: Mac sales of 18.75 million units for 2012 and 23 million for 2013. At least.

— Dennis Sellers