Besides, "low" is meaningless to us gas stove users. What, you want all instructions to be made just for you
, huh, Lib
But, yeah, package instructions are pretty worthless. Except, now that I think about it, Rice A Roni instructions were actually pretty good. But they were the exception, of course.
For anything that will scortch to the bottom of a saucepan like sauces you pretty much want it as low as it will go and still see a bubble come up now and again (one here or there every second, maybe?). For something in a regular pan that is too wet to be considered to saute then I would usually consider a faster pace.
So, the answer would be depends, depends, depends. Depends on what, in what, and with what.
Next up: best way to set the dial on an oven!