The pulley that used to be on my Volvo has been changed to another model by a certified Volvo service shop in St. Martin 2 years ago. The change didn't impact the lifetime of my alternator belts.
In regards to the timing belt, based on the answer I received, I now think 1200h should be o.k., so I don't need to do this now at 800. If someone has pics and / sources to get the special tools, I'd appreciate.
SY NO STRESS