MPIX Highlight ?

Hello, I have MPIX's monitor profile and the prints match my screen very good. I have a white point in my photo that measures 250/250/250 RGB and I also have another white in the photo that measures 235/235/235 RGB. I was expecting the 235 whites to be a little darker than the 250 whites. When viewing the print they look the same. Wouldn't you think that the 235 white would be a little darker? So, should I expect any whites 235 and above to be white? Anyone else see this? Thanks, Alan