If the character determines the stress track based on the attribute(s) used to defend this opens up a lot of tactical options really. If you use Daring+Reason to defend against a sword you could choose to take stress to the Confusion (Reason) track and as that gets whittled away you can then choose to take it to the Fear track (Daring).
If I’m reading this right I absolutely love this, giving incentive to change up your defense to spread stress around some. Brilliant idea.