Guild Wars 2

I would love for someone to explain a bit to me on the specifics of diminishing returns.

So I run a dungeon, get 26 silver. I run it again, 26 silver. Run it again, 13 silver. How long do I have to wait from this point in order for the reward to reset to 26 silver? Or is it at a set time everyday?

Also, most people say that you can do a dungeon on one character then hop on another character for full rewards. However, according to the wiki, it says diminishing returns are account based.

Could anyone clarify?

I believe it’s 30 minutes since the last completion to get “full” rewards, which is 26s + 20 tokens. I ran Sorrow’s Embrace 3 times yesterday and received 20 tokens each time, but I waited somewhere between 30-60 minutes between each completion.