My recent experience:

Had one personal (10/3/16) and one business (1/17/17) card. Canceled my personal on 4/10/17. Had not read the new churning rules and did not lower my CL on the personal. However last week I did lower the business CL to $1k.

Applied last night for a new personal card and got the "pending" language. Just checked the website and found I was approved.

I am now at 17/24 (actually 17/17).

Thinking of canceling my business card soon, waiting a month, and applying again for that card.