I had a very different experience, in which my Amex charge spending did very negatively affect my credit score. I had several months in which I spent well over 100k on my Amex charge card, which was reported as a "balance" and used as part of the "outstanding debt" portion of my utilization percentage (even though, of course, it was paid to zero each month), and that very negatively affected my FICO score. (And the fact that I routinely paid these amounts on time did not seem to factor into my score to improve it, either.)