I'm having this problem, too.  There's really been some odd behavior - e.g., somehow getting many more possible "transactions to match" when I NARROW the date range!

In trying to follow your recommendation, though, Klent, I get as far as Step 5 - where is the "Suggested Matches" toggle?  I don't see anything like that on my screen.  Under the header, the option fields are "show", "search", "from", and "to".  The next line is simply, "Select transactions to match".  The gear to the right brings up an empty field.  There are the boxes to check for each transactions, of course, but the only other options on the page are "resolve difference", "cancel" and "save".  

I see your note is from just a few months ago - could the layout have changed in that time?