If you're using a VPN, you're hiding tor from the ISP but not from the VPN.
Discussion
According to whonix its essentially impossible to Hide Tor from your ISP
"it has been concluded this goal is difficult beyond practicality"
I'd assume they don't think using a VPN is that difficult.
A good VPN encrypts ALL traffic.
The ISP only sees encrypted traffic between you and your VPN provider.
There's absolutely nothing they can do to know if you're using Tor except to subpoena the VPN provider for logs if they keep them.
You could argue they could do timing and size analysis on the encrypted traffic but even that only gives a likelyhood of tor usage, not certainty.
I see, thanks for clearing it up.
Im guessing whonix meant they couldn't figure out a way to hide from IPSs?