I think you misunderstood what Timo was saying. To me the “gist” of your question looks like this:
“Will the cost of going from the previous version to the latest version remain the same?”.
The question looks like that because this thread is about what was the latest version at the time, v8, and you were asking about the upgrade from 7 to 8. So when Timo responded above it looks exactly like what happened: The upgrade to the latest version from the version before it is now less expensive (i.e. $200 instead of $250).
As far as I remember it’s always been the case that if you try to upgrade from a version that is older than the previous version it is more expensive. So from 8 to 10 is less expensive than from 7 to 10 - just like it was more expensive to upgrade from 6 to 8 compared to 7 to 8.
The whole point of having a grace period is to get people to upgrade sooner rather than later, and the “reward” for people that do that is that they get the next version without paying more once it’s available. From what I can see online:
7 to 8: $250
6.5 to 8: $350
6 to 8: $450
…and so on…
So I think you just misunderstood somehow.