Absolutely, every time (bar once - see below). yes. Clear enuff?Top hat washers on a ceramic basin?
If you have ever cracked a basin trying your hardest to get a metal backnut to hold the tap, suspect cheap imported basin with an high-spot, tight you'll know, just know why.
Oh, and why oh why are new/replacement tap threads getting shorter?, well one thing is for sure, it is not for my benefit.