I don't see any point in doing this. I can see a visible, if slight difference in tone between printing a 255 white vs a 253 white on an Epson 9900 that I've custom profiled. So if you knock your whites down that far, you're also leaving a lot of dynamic range not he table. The shadow end is a slightly different story, and while the profiles are pretty good at maximizing the shadow detail, you will still lose pretty much everything that is below about 10 or 12 in your original file - and I'm referencing high quality photo paper using PK inks. Matte papers lose a bit more of the shadow details. Just one more thing to be aware of when printing.