A few things.
- Labels should not be centered, it's awful for eye movement and legibility.
- I would favor the ease of the user experience over the conservation of html elements here, even if the form has to be longer.
- Also, the eye movements necessary to navigate this form are crazy. By having two columns with a label on top of each, the user has to constantly move back to the column header to remind themselves what option they are modifying. It's not a long form, why be so conservational?
- I would use contrast to afford the secondary text to being optional, a help text.
This design makes the form longer, but as a user, I don't care--especially when it's not a long form to begin with. I can go from the top to bottom quickly without having to rescan the whole page every time. Each individual element can be isolated as my area of focus.
In fact, for users who know they don't have to actually target the little checkbox, but the entire checkbox and its label as a clickable area, it should look like this: