Here's my take. Don't get caught up in ranges. Go by what your doctor says and what your lab states is YOUR range.
A safe normal postprandial (2-4 hours) has been considered <180 mg/dl. eating
the proper foods, the obtainable goal has been <140 mg/dl. These are goals for diabetics and non-diabetics. However, these goals may not be correct for medicinal induced diabetics; one that has diabetes as a side effect of medication.