A bit confused when using Baking soda and sea salt mixture
The only reason I could see not using it is for the same reason Eagle said. If your hair is too oily, it means it's already too acidic. Adding ACV will just keep it acidic, thereby keeping it oily. If you want to reduce oiliness, just use the ACV once a week in very tiny amounts. As the oiliness goes away, increase how often it's used. Then, as your lock mature, increase how much is used, and then how long it's used for.