Hi, 

The describes posting types are not driven due to a localization but core functionality. These are rental related posting types. Specifically discounts on the customer order rental. 

Rentals is a separate option on the customer order. A customer order can have sales lines, or rental lines.  Clients typically need to post sales vs rental differently. The noted posting types are very similar to the sales posting types for discounts, the described posting types are for the rental related transactions and discount's 

Image of a customer order showing sales lines and rental.  The described posting types would be driven due to discounts entered on the area for the rental transactions (rent out). 

You may or may not have the rental functionality.  If you have the rental functionality and access, you will see a good number of screens / functions for rental - rent out (customer orders) or rent in (purchase orders).  Note Rental is an optional set of components, you may or may not have the functionality. 

Best regards, 

Thomas