S-Health (S6 and G3) step aggregation

[AC Question]

Using a Gear3 connected and synced with S6, i can view the Steps on S6 in the options (all, mobile only, gear3 only). Assuming, that there is some smart algorithms not just summing the two values together when cariing both devices in parallel, the values do not sum up. However, in a test szenario walking 30 steps gear and s6 both increases by 60 and the Step Counter on the mobile with the option "all" increases by 100.

I missed to find the manual, or at least a description for the apps describing the values when using it in synchronous mode.

Any advice?