Pricing Criteria Score is not being Automatically Calculated even though Prices have been entered.
You might have entered a '0' under Price for one of the vendors, which will return '0' for any scores.
According to the Pricing Score formula:
Score = (Lowest Cost / Cost Being Evaluated) X Pricing Criteria Weight
If that particular vendor is disqualified from the Project and no longer require a Pricing Score, completely eliminating that vendor will save the need to input a price.