Done. I've written the forecast change note to `output/drivers-note.md`. 

**Summary:** EBITDA fell ($149K) from Prior to Current primarily due to active customer decline from 46 to 44 (hitting EBITDA by ($133K)), partially offset by gross margin expansion from 26.2% to 26.6% (adding $39K). Headcount increased slightly, reducing EBITDA by ($54K). The note asks for documented assumptions supporting each of the three changed drivers.