Since chefs use kosher salt almost exclusively, and write many of the recipes you see online, that’s the type most often used. When you combine that with the fact that most home cooks typically use fine salt, there’s going to be issues.
Basically, if it’s not a recipe you can season “to taste,” and you’re using fine salt for a recipe that calls for kosher, then you’ll want to use about half the amount. Of course, it would be nice if every recipe were written in weight, but that’s not about to happen, and besides, there are already a trillion recipes out there.
So, why do chefs like kosher salt so much? It’s easier to handle, and doesn’t clump like fine salt. That’s big in a moist kitchen. It’s also nicer looking when finishing plates, as you can actually see the flaky crystals. Lastly, it’s a textural thing, providing a little crunch on occasion. By the way, there are different kosher salts, and other coarse salts on the market, but you can find all kinds of conversions online to fine salt. Good luck, and as always, enjoy!