That's true. They don't.
On the Dashboard, the "days" numbers that appear under each listing are not intended to depict market time. Rather, they merely define a near-term range for a quick activity status on each listing.
The day range is typically not greater than 30 days. Further, the range is not affected by a short off-market period of several days.
When There is an Unusually Long Period of Time
On occasion, for a new listing, you might see the metrics on the ShowMojo Dashboard display for 300 days or more. This typically happens when an existing listing is taken back on market.
This is something that can occur for a couple hours, and should always resolve itself. This temporary issue occassionally arises because, for performance reasons, ShowMojo cannot calculate listing metrics in real time.