Was thinking about support for drawer slides. Decided that the vertical load is mostly at the front of the case so i add support there.

ex; If a loaded drawer weighs 20 pounds, the back of the slide will need to support only 5 pounds per side when the drawer is shut. At the front it will need to support 15 pounds per side when the drawer is open.

So if using a 100 pound rated slide (per pair) does the rating allow for the 50% increase in loading on the front or is the rating only good for a closed drawer?