Is the high utlization on your Amex card?
They usually use the last SP they have on file when conducting CLI, do you know what your file looked like when they SP you last?
You can get the SP's by looking at your reports with the CB directly. The easiest way is to get your annualcreditreport.com reports. These are pulled directly from the CB and will show HP and SP. Experian is the one you want to look for with Amex.
Yes!! The only difference when I got my CLI was 90 days more age and $0 balance. On my previous denial for CLI I had a balance of roughly 30% dropped to zero and wham CLI.
I'm in a similar situation and have decided to wait on the CLI. While it would be nice and help overall util a bit, I don't want to push my luck with them. It could be fine, but the high util could be a red flag in combination with your wanting to raise your CL with them. IMO, better to err on the conservative side and not CLI until your util has gone down.