The circumstances you summarize may be correct but other possibilities exist.

They may not be spending a lot of valuable time on this particulat project.

They may be evaluating many potential infringers simultaneously and plan to announce multiple suits of letters of infringement at one time.

I doubt thay are working on a single case in that it would require several  months or years to evaluate and declare some 174 individual lawsuits.

As has been stated by Blakeley, this quarter will provide additional details pertaining to DMs strategy. As a result the window of opportunity will become more transparent.

I look forward to the next patent issue announcement.