At DataHawk, we want you to get as much value as possible from using our tool. As such, each Keyword and ASIN you track on DataHawk counts only once towards your plan quota. In other words, a Keyword that's relevant for more than one ASIN will count once only per marketplace.
To give you an example, let's assume you're tracking 5 ASINs on DataHawk on the Amazon.com marketplace, and that all of those are leather goods. In the same Project, you've added the Keyword "leather messenger bag" to your Tracked Keywords list to monitor how your 5 ASINs are ranking for it. In this configuration, you've used up only 1 Keyword and 5 ASINs.
Note: This is why we recommend to our users to consider the "overlap" in keywords between their products. The real Keywords usage you would have is generally much lower than what you expect.
Keywords are counted on a per-marketplace basis. This is as, naturally, search queries results are different across different marketplaces. As such, if you have a Project tied to the Amazon.com marketplace in which you're tracking "messenger bags", and you're tracking the same keyword on the Amazon.co.uk marketplace, this would count as 2 used keywords in your account quota.