Similarly to Timestamp modifiers, could you add a Hover format option? However, it wouldn't act the same way, instead, it would use $ as a placeholder for Hover text, this way you aren't restricted to a prefix/suffix like you are with Timestamp modifiers (prefix).
If you really wanted to, you could even make the placeholder customizable (Hover placeholder), in case people want to use $ in the Hover format.

Example:

• Hover text: ss.SSSS --> 49.0109
• Hover format: $ seconds --> 49.0109 seconds