SOLVED. a book about girl on space ship doesn't know its space ship. lives lower levels cleaner. cleans pipes. finds more levels they expand. the upper levels are higher A [s]

[Lisa]

girl living in lower levels people down there have low jobs low class status. She is a cleaner cleaning pipes. Lower level people keep the place running. Upper level people have better jobs and better lives. She finds out they are on a space ship. They rebel and take over and find more levels and expand. Another ship turns up of people who were banished to a smaller ship.

[Kate (Feathered Turtle Press Reviews)]

No idea if it takes place on a ship because I only read part of it, but the other stuff seems to fit: Inside Out

[Lisa]

Yes that is it. Thank you so much