Should you ever deviate from basic strategy due to the count? Lets take for example a situation in which the dealer's up card is a 4 and you have a 12. Basic strategy would tell you to stand and not hit. Now consider the count is extremely low, for the zen count, suggesting lots of '10' cards have been drawn already. Lets make it absurdly low like -14 or something. It makes it less likely then that the next card drawn should be a 10 value to have you bust. Should you hit in this scenario or is basic strategy always the way to go? On the other hand, a really low count makes it likely that the dealer then picks up a lot of lower value cards hopefully busting. I'm confused if card counting is simply for betting strategy or if it should be regarded as a way to alert you to opportune deviations from basic strategy.
The short answer to your question is YES. This is the whole reason for counting, to understand how to change your bets and strategy to account for the count and to take advantage of the change in the odds.
This is also how casino's know that you're counting. Once they are deep into the deck, you start betting higher, which is a signal to them that you're counting, in which case, they'll escort you out the door.