Been more than the value of the car for 10-15 years (maybe more). By the time the first of those motors failed they already were too expensive.
Living in Florida and having only worked on these cars for near 30 years that is not long enough to have ever had a call for the motor on a 110 body. The 108 body is similar and I have had people that inquired about a heater motor for those cars.
All of the cars with separate heater and A/C blowers have long since had the car totalled by a heater blower. Maybe the 113 chassis would be an exception.
Bosch Master, ASE Master, L1
33 years MB technician