[Pro Sites] Any way to shorten period of time (rather than "extend")?

On the Pro Sites Management page I see how I can manually extend the time period for a subsite. Is there a way to shorten the time period? The workaround I found was to first "Remove Pro status from this site" and then redo the Extend with the (shorter) time I wanted applied. Just want to make sure I am not missing something...

Thanks!