First of all, Congrats on your CLI!
I have the card for over a year, it was at $5500, then after a fraud and some financial struggle over 6 months ago (all my limit maxed out etc...) they reduced my limit to $500. I have a general utilization of 1% now, and I've tried in the last few months to get my limit higher with no luck. After seeing your post, I was like why not trying!
I tried $750... Got approved for $1500! I clicked again "Request more" and asked for $5000, and got $6000! I won't try again but nice! Thanks for the tip!