Worktoplay,
My thesis is that DNAG will seek to protect some of their most important property by placing it outside the view of competition for as long as they can.
A continuation needs to be filed before the issue of the patent in question, which is valuable, nonetheless.
A reissue, however, assuming all conditions are met, would protect the property from competitive eyes for another two years--it must be filed within the two year period--which gives DNAG more time to acccumulate revenues in order to be able to afford to defend an infringement.