Hi Pienne,
In all due respect, I have some doubts as to the appropriateness of the word "virtually" in that context. I think we might encounter the usage of that word in some other contexts and might not be right in this particular context.
I think it might be more appropriate, if not just appropriate, to say like this:
They mean basically the same. They mean just about the same. They mean almost the same???
Please tell me if you think otherwise.