After reading the accounts from different people. I'm of an open mind... As long as your capable of sorting it out yourself? Then do what works..
Me? I'm from the old days of peeing in a chemistry set.. "If you feel funny? Eat." Even with the pee sticks a hypo would cause colourblindness, thus matching the colour chart.

I'm still fully hypo aware. Which even wakes me.. Plain & simple I feel "stoned"... I'm never wrong.
So I eat first.. Testing with a meter within the first 5/10 minutes while I drink or chew on something gives me a gestimation with respect to "lag". A reading of for instance 2.5 or 3.6 Maybe the lowest point I dropped 20 minutes ago? Or where I was 15 minutes back before it dropped further..
"Testing first" & getting a 4mmol may not seem that urgent but the reality of the BS at that moment may be lower due to that lag. I get the sugar down first.
I read a fair few posts on hypos where the testing is every 5 minutes & the BS don't go up fast enough... Some mention the BS even drops a little further & they panic & end up "over treating"..? "Lag"..
However accurate the meter is.. It's a "time machine".. You still need a little instinct.