Mabey it's because money is / has been tight, my Daughter bought some paint from a local well known DIY Centre, what a sheer waste of money, using the undercoat is like putting water on the wood I would have been just as well using white Emulsion to cover this stupid dark Red her previous B.F. Choose. Moan over.
I agree, I have just started my Daughter's bedroom, the knob she was with was very dominating & she went with the flow, you have to see this room to believe it, Very dark red walls, yellow Skirts & window sill, it's no wonder the clown had dark Syndrome, regards the paint, I know money was tight at that time, but it was a sheer waste, she's bought the cheap Emulsion paint for the walls with the final 2 coats of Dulux.
We always use it to cover tenants gaudy colours and has done us well for the last 15 years or so. I've used it in my own home too to cover my daughters purple, then covered it with a final coat of a good quality paint.