Exemptions in general, Phase I and Phase II, must be reviewed annually and the only reasonable interpretation means that's every 12 months. A competent outside analyst will expect that the review will be documented. The easiest way to document the existence of a bank is to find it on
Bank Find on the FDIC's web site, print out the page, and attach it to your review sheet. (Your browser should show the date printed at the bottom.) I don't have a pat answer for credit unions, but will amend this post if I find it.
Generally, it is not necessary to do an annual review of a government entity if the name of the entity clearly indicates it is governmental. (I'd appreciate hearing from anyone who has been told something else and exactly what it was you were told.)
Voila: Find a Credit Union