But surely one of the problems with home BG monitoring is that it is an instantaneous check. If you are 6.2, then are you 6.2 and on the way up, on the way down or fairly static? Put it another way, you could have been on the way down to 5ish or lower, and the food brought you back up again??
Edited. - also factor in your meter error of +\- 15% of your true BG level. 5.6 + 15% is nearly 6.2 (in my head) and 7.3 -15% is around 6.2. So you could have started off anywhere between 5.6 and 7.3. Do the same thing with your 'after' result and your BG could in theory, actually have gone up even though your meter reads lower!