Thin,soft crust development and dark color in retarded SD breads

Hello,

         I have been baking for 3-4 months,most working my way through Forkish's yeasted and pre-fermented recipes. I have started baking SD both with the NFNM starter and with a 65% hydration bread flour recipe I got from a great local bakery which was offering classes.

     I have noticed a few things recently since I have started doing SD and retarding for 12-14 hours in the frig. I am baking in a dutch oven. The first thing is that the loaves seems to color more quickly/deeply once removing the lid. Not that I mind because I love a deep dark crust,just an observation. The second thing I have noticed recently with a few loaves made with the bread flour starter;the crust seems thinner and softens up a bit after being out of the oven for several hours. Not exactly leathery but I can't think of any other descriptor to use. Sorry,no photos,I gave both loaves away ;<)  Are these crust issues happening due to the overnight retardation? It seems like my earlier loaves (straight yeast or pre-ferment with no retardation) had a bit thicker crust that stayed crisp/crunchy. I notice that with the retardation in my banneton (with no cloth liner) the top surface of the boule is dried out to an extent. I am finding that I like the schedule flexibility of retarding doughs as well as the fact that I like the fact that they are firmer when it comes time to unmold and bake them. Easier to handle and score with less deflation. I've actually experimented with retarding some yeasted breads with good results.

FWIW my recipe is 80% bread flour,15%whole wheat,5% rye and 80% hydration.

     Anyway,any thoughts or comments will be greatly appreciated.

Best,

         Vance