The Rulebook states the following:
"Each result of 4 or 5 cancels a Hit or Critical Hit chosen by the shooting player, and each 6 cancels a Hit or a Critical Hit chosen by the target player."

And I need to ask if I understood this correctly. I'll use an example.
Tank A shoots Tank B, scoring three 6s. Now Tank B rolls its Defence Dice, scoring three 4s. Now, the attacking tank (Tank A) has to "use" the three 4s to cancel his own dice, and since there are no normal Hits, he uses these Defence Dice to cancel his three Critical Hits. In the end, Tank B remains unscathed.

Is that correct? In my previous games we used Defender's 4 and 5 to cancel 4s and 5s (not respectively; a "Defensive" 4 could cancel a 5), and 6 to cancel sixes. Which way is the correct one?