Special Education teachers are almost always assigned to a single school, with a single principal as their boss, working with a few dozen students for the whole year. Occupational Therapists who work with schools typically work with several, or even dozens of schools, and have a supervisor at the district level.
Increasingly, OTs are providing fewer direct services to students. It used to be that when the OT showed up, the teacher sent the child with the OT, they went somewhere, and did things together. Then the kid came back to the classroom and the OT would come back in a week or so.
That still happens a lot, but the trend is for the OT to work with the child long enough to find out what the fine and gross motor needs of the child are, then consult with the adults who see the kid more often.
In other words, if the OT determines that certain exercises will be beneficial to the child, they will teach the teacher or the educational assistant how to take the child through those exercises. That way, the kid gets to do them more often, but the OT may not see the kid again for months, or ever if the exercises work.
Ultimately, it's more beneficial to the kid, but some teachers are used to seeing the OT as the person who takes a kid out of their too busy classroom for a while, not as someone who comes into their too busy classroom and gives them more work to do. You get some tension there, sometimes.
In my school system, it's a bit unusual for OTs to stay more than a year. OTs have job opportunities outside the school system. If the system treats the OTs anything like the system treats the SpEd teachers, the OTs just go work somewhere else.
Both positions have a great deal of paperwork. I train SpEd teachers and OTs how to use the computer system that manages our documentation for services. I may train some OTs this afternoon, in fact.
SpEd teachers have a large amount of paperwork for each child. Federal law requires progress reports every quarter for each child in SpEd, Individualized Education Program review at least once a year, and a reevaluation every three years.
In my district, OTs have to do a service log--five minutes maybe--every time they see a child or consult with somebody about the child. An assessment may take a few hours of paperwork time, though. If there are OT goals in the IEP, the OTs are supposed to contribute to the quarterly progress reports, which requires some coordination and communication with the SpEd teacher. There's some tension there, too.