予定 and 見込み: a plan and an outlook based on current conditions
Compare a plan to send materials with a forecast of completion, distinguishing the planned date from the expected date when they differ.
A plan for what will be done
予定, read よてい, means a plan. 来週、資料を送る予定です。 says that sending the materials next week is planned.
会議は午後に開く予定です。 says that the meeting is planned for the afternoon. It does not report a meeting that has already taken place.
An expected outcome based on conditions
見込み, read みこみ, means an outlook or expectation. 作業は夕方までに終わる見込みです。 says that the work is expected to finish by the evening.
この調子なら、明日には完成する見込みです。 says that completion is expected by tomorrow if progress continues at this rate. Keep the condition この調子なら with the expectation.
When the plan and outlook differ
完成の予定は明日ですが、今の進み方では来週になる見込みです。 says that completion is planned for tomorrow but expected next week at the current rate of progress. The plan and current outlook differ.
A plan or expectation does not establish actual completion. Distinguish it from wording such as 終わりました, which reports a completed event.
What completion time is expected at the current rate in 完成の予定は明日ですが、今の進み方では来週になる見込みです。?
Show the answer and why
Next week. Tomorrow is the planned date, while next week is the outlook based on current progress.