Check out this picture.
<a href="http://www.airlinemeals.net/images/meals/unitedairlines538.jpg">
I wouldn't say Delta3MM is wrong since K for kilo means 10^3.
Thus 100*10^3 can be 100,000.
But I think the K of 1K doesn't simply imply kilo.
It's just the name of a status.
Why would UA bother to use 1K for someone's stub and 100K for other's stub?