If activity is detected on an account that may warrant a SAR, but then we learn of additional subjects and types of transactions that should also be included on the SAR, does the 30 day window begin on the day we last detected the most recent information that should be included on the SAR?

My understanding is when the decision is made that a SAR filing is necessary the 30 day timer starts. Any additional information found after that time should just be included in the filing.

The countdown to file a SAR starts when the appropriate person(s) determines a SAR should be filed. If you find additional information you can include it prior to filing, amend the SAR after it has been filed, or include it in the continuation SAR.