I have a 22x25 single sink with vanity. I have purchased two "off the shelf" sinks that fit perfectly but returned, so I know its not the vanity. I then ordered another sink, which cost alot more, waited 2 weeks, and when it is set on top of the vanity, it doesn't sit flat. I would guess maybe 1/8 inch? Can this just be leveled and secured with a shim underneath when its installed OR am I going to have to send it back?? This is so frustrating!! Any comments would be appreciated.