If you plan on assessing a small amount of candidates each year, then the pay per assessment will be more cost effective. However, if you plan on making multiple hires and want to make the best hiring decisions by measuring more data earlier, then the Licence Agreement is best for you.  By assessing more candidates earlier in the process, you are able to include candidates that are the right fit for your team, company, and mission, whilst minimising bias in your recruitment decisions.