What improves after import
- Target internal column names become more accurate.
- Required flags can reflect SharePoint configuration.
- Date, Boolean, text, choice, number, and person-like controls are easier to classify.
- Suggested and unmapped rows are easier to review.
Merge behavior
Import should preserve manual overrides unless you explicitly reset mappings. That lets you load fresh columns without losing a builder decision you already made.
When to clear imported columns
Clear imported columns only when you loaded the wrong target list or when the destination list changed enough that a clean import is safer than merging metadata.

