First of all, I have to say that I am impressed with your mathematic calculations. I would need a calculator to get to the same conclusion. 2 hours if you take it in. In my case, it is a 13 min drive to the nearest authorized dealer so, let's say 30-45 min tops give or take. I know, I know: Those 40 min every 2 years could be a massive waste of time if I manage to live long enough to celebrate my 118 Birthday...
Also, that speed, precision and mechanical inclination of yours is WAY above the average bloke, legendary lv. I would say SO please don't compare yourself with the rest of us, incompetent apes.
AND, I checked the web only to find that the 2 hours express service is NOT exclusive in Germany, some UK dealers do it as well, go figure... IF only we could pick-up our smartphones and make an appointment in advance... of course, that would be like asking you to eat lava so crazy task I guess...
Mike's Dive Store is a fully authorised Suunto Level 1 service centres in the UK capable of carrying out all Suunto battery changes and servicing in-store.
www.mikesdivestore.com
ps. What is a screwdriver?