The profiles that I usually consider for typed response as an accommodation include:
oral expression > written expression
any reasoning index (VCI, PRI, VSI, FRI) > processing speed (PSI, or just the Coding subtest)
verbal cognition (VCI) > written verbal achievement (written expression, writing fluency/output, written mechanics)
quality of written expression (i.e., composition skills not scored for mechanics) > written mechanics
brief written expression (sentence length) > extended written expression (essay/paragraph length)
Psychoed assessment is involved most likely because they are attempting to document educational impact to justify the specialized accommodation of typed response. (Though one would hope that sometime in the very near future typing for long essays would become a standard accommodation for any student!)
Of course, any below average result from OT/fine motor assessment, or, presumably, a doctor's note stating that her joint hypermobility is a medical condition affecting prolonged writing tasks, ought to support typed response. She's reporting pain while writing extended pieces, which, one would hope, would be a shoo-in for typed response.
