What does your overall credit profile look like? Is this the only account that's maxed?
If so then you may want to call them to discuss it. "Hey, I see my limits continuing to decrease. Can I make (big payment amount) to stop the decreases? I plan to continue making large payments to pay it off by (date)."
No harm in asking, I don't think. Be prepared for a No, but they'll probably work with you unless the rest of your credit profile looks "stressed."
My impression is that there was an algorithm within AMEX that initiated your CLD. If they haven't balance chased you for 8 months (I believe I read that correctly, that the CLD was 8 months ago) that seems like a positive thing.
I like the 3X approach in the future.