ALTs who teach at 5-6 schools? Is this even possible?

Saw this on another thread and didn't want to hijack it. Some people had stories of ALTs assigned 5-6 elementary schools. How would that even work??

Virtually all elementary schools are years 1-6. Years 1-4 get one English lesson per week, 5 and 6 get two.

So worst case scenario, you'd teach one class to every single year at school A on Monday, every year at school B on Tuesday, every year at school C on Wednesday. Thursday you'd need to go back to school A in the morning and B in the afternoon to teach years 5 and 6 their second class, and Friday school C for their years 5 and 6.

Where can you possibly fit in schools D, E and F? (And that would be the absolute worst case scenario)

Not saying I'm skeptical, but unless some schools are skimping on English class (against MEXT requirements) it doesn't seem possible to teach at more than 3 schools.

Genuinely interested in how this could work.

EDIT: and this is assuming you only have tiny schools with one class each year.