@sartoric ok, i have downloaded the FIT file and converted it in Excel file.
If i take altitude point every 30s and keep only positive ascent i find a cumulative ascent of 3549m instead of 4100m in suunto app.
3549m seems closer to the right ascent.
Can someone of suunto support (@isazi ? @Dimitrios-Kanellopoulos ?) look at this issue ?
It seems more a Suunto App issue
Update :
same with every 15s, i find a total ascent of 3692m
algorithms from Runalyze give 3538m