Sorry to hear Glenn... but join the club... the endless battle!

There are two other things I've found to lower blood sugars.

1) Theanine has lowered mine a bit. This works by blocking cortisol.

2) The other is high dose Biotin. Taking lipoic acid all the time, may use up the internal transporter...which is shared by lipoic, B5, and biotin in the body. Taking 5-10mg of biotin a day, at an alternate time (I take it at night) may have a positive effect on your glucose control. It is reported in the literature as such.

But all in all, you are still in a fairly okay place with your numbers. I don't have that low a fasting anymore, but my A1C is the same as yours. They really don't start "treating" until 6.5 or 7.0 these days.

Also the A1C reflects the size of meals as well. Not just content.
So eating smaller may help.

Here is a handy A1C chart:
http://www.diabeteschart.org/bloodsugarchart.html

There is a trend just with aging... to slightly go up anyway IMO.