Confirm it with the Nebraska DMV rather than assuming. The period runs only while a valid certificate is on file, so lapses push the end date out, and the safe move is to keep the policy until the state confirms the obligation is closed.
More detail
The most avoidable mistake at the end of this process is cancelling early. A driver counts the months from the violation date, decides the period is up, and cancels. If there was a lapse anywhere in the middle, or if the clock started later than they remember because the first filing took time to post, the obligation was still running and the cancellation is reported as a lapse. That can restart a suspension at the moment the driver believed they were finished. Two safeguards: ask the DMV directly to confirm the obligation is satisfied before changing anything, and tell your producer the confirmation date rather than asking them to guess. Once the obligation is genuinely closed, removing the filing is also the moment to re-shop the policy, because the record is now cleaner than it was.