If your refresh rate was something like 75, like my main computer, then there would be a difference between + 1 and 60 * TimeDelta. To achieve the equivalent of + 1, it just becomes (your refresh rate) * TimeDelta.
So basically, if you want your game to have the equivalent of what + 1 is on your computer, but still run the same on everybody's computers regardless of refresh rate, you'd just use (your refresh rate) * TimeDelta