Hi!
In Sweden there are OTs working with assessments regarding peoples working abilities, although I'm not sure to what extension they are involved in determining percentage or hours. Some use an instrument based on MOHO that uses the individual's own assesment that is called Dialogue about working ability. You can read more about it here:
https://www.arbetsterapeuterna.se/Om-forbundet/Forbundets-forlag/Dialogue-about-Working-Ability-DWA-version-40-2012/
Best regards
Elin Widmark
Occupational Therapist, MSc