Staff accounts, QA devices, and unfinished installs inflate early steps and flatten later ones. Exclude them in the contract, not as a last-minute filter.
Mixed windows—same-day for step one, seven-day for step four—produce rates nobody can compare week to week. Pick windows deliberately and print them on the report.
A rising conversion rate after you removed a required field is not always a win. Pair conversion with completion quality and support volume before celebrating.