Think it through: what's special about the middle of the table? It's the balance point. Either side of that you've got more weight of the table on one side than the other, which pulls against the ways making the assembly more rigid and introducing a little extra friction. Hit that balance point and all that goes away.
I climb cut a lot on my old bridgeport. I know tons of people will tell you the sky will fall on your head if you do, but I've learned when I can and genuinely can't. Keeping on top of the gibs and backlash adjusters and using just a little bit of drag on the lock of the active axis, while making sure the rest are locked up tight seems to do the trick.