First, let me say, what's wrong with 85? That's a good number!
Just curious - why 1/2 banana before bed? Maybe try some protein if you need a bed time snack. Also, regarding the toast - it is not the sugar that matters as much as the number of carbs per slice. I can do 1 slice of lo-carb bread at one time, but I would usually wait until 10 am or so. I only do proteins when I first wake up.
Yes, I understand the dilemma of having to eat something every few hours - but I have to eat every few hours to keep my bs from going up, up, up - I know, seems counter-intuitive, doesn't it? Anyway, I haven't quite figured out why this is so, but I've discovered that just a bit of protein every few hours does the trick. As long as I go very low-carb, my body can naturally return good after-meal numbers - but it can't deal with the overnight fast or long breaks between meals, so I have to take basal insulin.
Your issue may be related to whatever oral medication you are taking. For example, if you are taking a sulfonylurea, it stimulates your beta cells to secrete insulin for 8 - 12 hours whether or not glucose is present in bloodstream; in other words, whether or not it's needed. In addition, these meds can cause hunger (I'm talkin' real, gnawing hunger) and weight gain, and because it can drive down your bs, you can be in the position of "eating to your medication."