Rett,
Good day to you.  No it isn't too late.  Install 2 Apistan strips, Now!
A vegetable grease pattie about the size of a large Mac, 3/16" thick
would be helpful as well.
   (G) :-)  I have spoken to Saint Anthony, (patron saint of beekeepers),
in your behalf, and he say you gotta get on with it.  Oh!  He also say,
"Tell that boy to read everything he can get his hands on about bees, and
ask questions.  Don't believe every thing you read, 1/2 of what you see
and doubt every thing you hear.  You have to find what works for you in
bee keeping or life.     Seriously.  To install the Apistan strips.  Move
the box above the brood box about 1" to the rear.  You must decide which
of the deep boxes has the greatest concentration of bees.  Work quickly,
quietly and very little banging or knocking.  From the rear, lift the
moved box up just enough to allow you to insert two strips in between
frames in the center of the hive.  Three frames apart.  Lay the pattie in
the center on the top bars.  Return every thing to its place.  Remove the
Apistan strip 45 to 60 days BEFORE your honey flow.
   You just might cause the cluster to tighten up, but unless you leave
them exposed for a few minutes to a cold blowing wind, every thing should
return to normal shortly.  A cold weather bee cluster is an interesting
thing.  Old bees can handle cold better that young.  Young bees prefer
the cluster center whereas the older bees prefer the outer mantle.  The
cluster moves like a balloon being inflated/deflated.
   The key to this manipulation is to plan every step of what you have to
do.  See it in your mind, and play it over and over until it WILL happen
as you see it.  Works for me!  Best Regards, JonC Peacock