This AdSpec is sold in US Dollar and Euro on two different price list: Special and Standard. But once sold it can't be sold at another price. Therefore it also has a self-blocking record.
If I sell it now to one customer for a specific day the booking calendar will show it as blocked so that I can't double book.
Here is what the booking calendar for that item will look like. Please make sure to include the column AdSpec Name into the layout otherwise the second line would not show in red!
Example Out of Home: One AdPrice with a Placement "single sided" is blocking itself. This means that is availability decrease once it has been booked. Other line items with the same AdPrice, but the same Placement will be blocked, if you have created a blocking record for the placement to block "single sided" with "single sided" (itself). The Position Chart will handle this as if a "real" Blocking record with factor 1 exists.