My microwave oven has a "POPCORN" button. Its manual reads:
Touch this pad when popping popcorn in your microwave oven. The oven's sensor will tell the oven how long to cook depending on the amount of humidity it detects from the popcorn. See page 31 for more information.
Page 31 clarifies:
POPCORN lets you pop commercially packaged microwave popcorn.
(As opposed, I suppose, to popping kernels in a paper bag, which I also do.) Fine. Other microwave ovens have a similar button (though I must admit I haven't checked their manuals).
The problem is that my "commercially packaged microwave popcorn" bag reads:
Do not use popcorn button.
I've seen it on other microwaveable popcorn bags, too.
So... which of the two manufacturers is correct, and why? And why does the incorrect one claim what it does?