Ditto, no clue what either of those mean. Never, ever heard of adding salt to a dishwasher, certainly. Not in new ones, not in ones from the bad ol' days when they used way more water but actually worked.
I wonder if its based on average water hardness in the area. I'm in the north of England and our supply comes out of Buxton Springs (yep the same as Buxton bottled water) and is extremly soft so despite filling the salt it never asks for it to be refilled again as its not needed.
When I used to live in north London I'd be filling it up once a month as the water there is extremely hard - so hard that it'll kill your kettle within a year if you don't keep on top of descaling.
I'm pretty sure the majority of dishwashers sold here have salt compartments - I've never seen one without one.
Much of Ireland has very hard water.