said by Woodlane:
xPlornet has confirmed that Skype data does not receive any acceleration ...
Good. Without that confirmation, troubleshooting would be incomplete. I agree with your congestion conclusion.
HN7000S - 98cm Prodelin/2w "pure" Osiris - ProPlus - G16/1001H - NOC:GTN - NAT 18.104.22.168 - Gateway 22.214.171.124 - DNS 126.96.36.199 and 188.8.131.52 - Firefox 15/MSIE9 - AV/Firewalled by NIS2012