No, you misunderstand. You get seconds assigned to your token. It doesn’t matter where in the video you use those seconds.

So if you watch an ad you get say 60 secs of video until you need to watch an ad again. You can watch 30 secs, then skip 2 minutes ahead and watch another 30 secs, then you get an ad. In reality the times would be larger, but to illustrate a point.

In the current setup YT uses, if you watch an ad, watch 2 secs of video, then skip ahead of the next adbreak, you get more ads.

And yes as stated, a separate client can get around this. But as also stated there will always be ways around it, it’s just a matter of making it harder. If it’s beyond what a simple browser plugin can do, it’s good enough. And YT has been banning 3rd party clients anyways, so that makes it even harder.