I have been type 2 for 14 years and over the last year I have found that my after breakfast readings vary inexplicably. If my pre-breakfast reading is around 6.0 it jumps o 13 or 14, if my early reading is about 7.5 it only goes to 9.5 approx.
For the last 6 mths I have eaten the same breakfast and followed the same procedures during the 2 hrs afterwards.