Should my dentist have redone all of my engagers when we had to take new molds and start a new round of trays?

After an 18 months my teeth still weren't straight. Took new molds & sent in for a new round of trays. When we got them, my dentist just sent me out the door with them. Luckily, before I left, I realized some of my previous engagers weren't on the new trays. He removed the "buttons" from my teeth corresponding to the ones missing from the trays. Trouble is, I think maybe he was supposed to replace all of the buttons because the trays don't seem to line up with mine anymore.