What I did: I created a WooCommerce plugin that adds a custom price for products to be computed in a different way. The plugin offers the possibility to override simple products or variable products prices for a specific interval of time. In the admin area, a new column called “Clearance price” is displayed in the products table. Also, it gives the opportunity to choose which products the clearance price should be applied on.
The plugin can be found here: https://github.com/costibotez/Clearance-Price