Immigration's document list for a status CHANGE has a separate item for vocational-school graduates: the Senmonshi title must be proven for the education to count towards the Engineer status.
What it must show
States the title Senmonshi or Kodo-senmonshi
Bears the school name and seal
Your name matches the passport
Where to get it
The student affairs office of your vocational school.
How to get it
Ask the school for 専門士の称号付与証明書
Say it is for Immigration
For 専攻科 students, ask for the completion certificate instead
