Hi Morgan,
Welcome to our forum and thanks for contacting us with your question!
If I understand you correctly, there is a way to achieve what you want with
tooltip.formatter option. With it, you can define the comparison logic and control the content of the tooltip.
I've prepared for you a sample fiddle with an example implementation, feel free to adjust it as needed:
https://jsfiddle.net/BlackLabel/71cdgfj2/
Let me know if that is what you were looking for!
Best regards,