We just had new oak hardwood floors installed. They were stained on site. My question is that they don't seem to be perfectly flat. Where the grain is, the wood seems to be very slightly depressed. Where there's no grain the wood is very slightly raised. This is consistent throughout the house and only noticeable in sunlight or by running your hand across it. You can't feel it walking on it or looking at it in regular lighting. Is this normal?

Thanks!

Thats called dishout, where the softer grain is sanded out. Not what you'd want for a new floor.

Not sure i agree without actually seeing the floor..grain is noticeable in all oak floors that are plain sawn....
the degree is another issue...

sanding at an slight angle, helps prevent this...but does not eliminate the natural texture of grain