I have only worked as a school-based Assistive Technology Professional. However, it seems reasonable that there would be no specific mandate to focus exclusively on education for the non-school-based sector. According to Washington State University, the purpose of AT is to perform functions that might otherwise be difficult or impossible for individuals with disabilities. That is a broad mandate. It still seems that best practice would include defining the "problem(s)" and generating a measurable goal(s) to track progress or lack there of.
School-based AT then is specifically driven by the education model. Private or community based AT does not have such a narrow lens. Despite this difference, it seems to me that best practice is driven buy the client's needs and measurable goals. I'm curious to hear from others. Please share your thoughts with me on this topic!