Keystroke uses a best price method to determine the price of an item. To do this, it calculates the price from every formula that the customer/item qualifies for and then uses the lowest one. However, if any of the formulas has the Force Price setting enabled, then that price is used and other price formulas are not considered.
Note: If the Ignore Base Price setting is enabled, the formula's price is used even if it is higher than the Base Price of the item (or the Sale Price if the item is marked as On Sale). However, other price formulas are evaluated and if any of them give a lower price, then that lower price is used.
See:
Price Tables - General Information
Configuration Manager Contents