I paid off my Chevy Avalanche car loan two years early so I spent $24.99 for my online Equifax FICO score to see how high my credit rating had gone. 
It had dropped from 803 to mid-700's...???
The Equifax agent stated that this was due to my personal line of credit (prime plus 2%) being too close to the max $15,000 and that AmEx had "cancelled" my card.
I informed her that it had not been cancelled but I had simply switched cards from a personal card to the Small Business Gold card (with an introductory 30,000 bonus air miles reward and 1.5 points for each dollar spent as well as a CRA deduction for the annual membership fees) and that I had borrowed on my super low rate LoC to fill the allowable contributions to my RRSP that year.
I would never invest in a business model as flawed as the credit rating agencies.