My ping had gone crazy again over the last few days, whilst the connection stats didn't change.
Eww that graph looks horrible.. and a reboot doesnt seem to have cured it as it looks awful again.
Out of interest what gateway are you on. A reboot should have sorted it and/or put you on another gateway.
A couple of weeks ago I found one of the gateways appeared to be getting progressively worse in the evenings so I did a gateway hop - currently on ptw-ag01... although thats not a proper indication as the gateways have several different endpoints.
My router uptime is 26 days. Just in case you didnt already know you can get a new ppp session to try another gateway without having to do a reboot or resync from
> Connection Status
> Status (Arrow on RH side of page)
> Device Information > IPv4 Address > Disconnect
Then wait a few seconds, refresh page and then click 'Connect'