We all have a last bite as well, so that could equally be the datum. I would try taking my BG every 15 minutes during a long meal except I eat very quickly and I am not sure my fingers are up to it. Maybe someone with CGM could provide some data. As others have said, the important thing is to be consistent with your timings. I measure 90 mins after last bite which
@azure does not allow me to call post-prandial but seems to me to be a good measure of the effect of a meal. Note that I am type 2 on no medication, those who are type 1, type 2 on insulin or have RH no doubt have other requirements and regimes of testing.