I'm not sure what you mean by "level". If the test shows you are within normal levels there is no reason to snack.
Really depends on your blood sugar levels and your medications. if medications are adjusted right then it should not be necessary to snack between meals. eating lower carb will also help avoid highs and keep levels more stable (though medications may possibly also need to be reduced.
Here’s some advice from the MedHelp website and our Sugar Sense app on when to snack when you have diabetes:
You can find this on the Sugar Sense app by going to the home screen, and clicking the menu bar in the upper left corner. Tap Health Guide, then scroll to "Eat Right." Scroll down for "Smart Diabetes Snacking". Hope this helps!