well I reread your OP, I will bet you are checking your timing at Idle, check your timing at 5000 and see what it is. Some of the digital have bad cases of magnetic hysteresis. I had some digital 7 boxes that drop 1 degree per 1000.
I would really like to see a pic of the plugs.
Joe
I check it at 3000. My fuel air mixture looks good, no noticable annealing line on the ground strap of the plug of the plug
