The loans would be reported (if you are a CRA reporter) within your micro data file for the entire year (including anywhere you extended loans). When you are examined the examiners won't distinguish loans made before or after the area was annexed. They will, however, take that information as a performance context factor when evaluating your performance. So when you are self evaluating your performance be sure to include the "before and after" loans and temper your judgment with the fact that lending results may have been affected by the branch opening.It's a best practice to document your performance observations and explanations and present them to examiners as part of the performance context. It will impress examiner that you are so diligent and thorough (and thoughtful too).
_________________________
CRA Exam Preparation, CRA Performance Evaluations, Key Performance Benchmarks, & maps