Apology in advance if this is already covered.....

If I recalled, check out date is used to determine night credits. If I check in on Dec 30th and check out on Jan 1st, I will earn 2 nights credit for the following year. If this is still true and when I see promotion with "Stay between 7/15~10/14....", will I get 1 night credit when I check in on 7/14 and check out on 7/15?