Creditanalyst101 is right about using that page to find out how NCAO is calculated, but in the spirit of one banker helping another one let me digest that page for you.
In the case of a decrease in NCAO from one year to the other you have to ask yourself the following questions.
1. Did revenues decrease?
2. Is the company taking longer to collect {did A/R increase}?
3. Did inventory increase?
4. Did accounts payable decrease?
5. How about Operating expenses, did they increase?
One of those or a combination of several is the culprit. Answer those questions, and the answers will guide you.
May your cost of funds be low, your interest and fee income high, and you past dues nonexistent.