P1606 printer only flips on short edge when double side printing is requested

My P1606dn LaserJet printer is refusing to flip on the long edge of the paper when printing when in the both sides mode.  It only flips on the short edge even when requested to use the long one. 

I downloaded and installed the latest P1606dn driver listed on the HP Driver Site which is Version 14.30.53.595 released on 8/31/2012. It has not solved the problem. 

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Any thoughts on how to correct this problem would be greatly appreciated.

Thanks!