Have new oak floors laid and finished in place with bona traffic. The finish is too light - it does not match my existing hardwoods very well (didn't see finish on new floors until after bona traffic was applied). Is it too late to modify the color to darken and warm it up? Do the floors have to be sanded back down to bare wood to accept a stain? Only need a few shades darker -- not a dramatic change. Thanks for the help.