Hi,
Your evening meal will determine what you go to bed on. Yesterday you had a full roast dinner, which will have taken a long time to digest with a mixture of carbs, protein and fat. The 2 hour reading of 8.6 was still on its way down when you went to bed. During the night it will have come down some more, hence a lower morning reading. Normally a bedtime reading should be in the 5's, maximum of 6. When you wake up it should still be under 6, but sometimes this is affected by the Dawn Phenomenon and is slightly higher on waking. This is normal. Do you do your morning test immediately on waking? If you get up and potter about first, you will get the DP. Does this make sense?