Can anyone explain the logic of this? I thought the idea was to see how well you BG had recovered from the meal but to take it to the extreme, with a very drawn out meal, you could still be eating while testing. Surely timing after a meal would be more consistent.
There are a number of threads about this - including one where I explained this. If you want to,search you'll find my more detailed explanation, but basically it's to compare with a non-diabetic level.
Obviously if you're having a very lengthy meal eg a meal out, then you have to use your discretion for testing, but for normal meals you should time your tests according to meal,start time, eg breakfast at 7am, two hour test would be at 9am.