You can check, since the white rectangles should be situated in the centre of each colour patch, so in your case, it is sampling more than one patch, or in your screen shot the bottom row of patches is sampling part of a border, so it will be thinking the colours are greyer than they should be here.*
Another thing, I don't think it was mentioned, but you need to set the correct paper type when you print the test chart, to match the paper type you will be using, and of course use that paper type setting when you make your prints. You will sort it out, but it is a fair bit to think about if it is all new to you. The documentation I had with pp explains the detail quite well, but you need to read it and understand it.
Set the corners right, and watch those crosses vanish
Best wishes,
Ray
* what is actually happening, is that in the part you have shown, it is expecting, at the left hand white rectangle the sample area for the white part of the white to black strip, but since you have in fact set the wrong location for the bottom corners, the scan area is compressed, and the sample patches will not line up with the correct colour patch in many cases. It shows it is sampling the border colour - a grey, when it expects white from the white to black strip. The next one over is sampling a bit of border and a colour, not a near white, and so on . You will probably find that some of the bottom row may not have crosses in the middle region, but just re scan the test chart and printed test again, with the correct corners selected, and get your money back on vuescan...