If a forum newbie can interject here, that thread seemed to bounce around the issue and not face it directly.
Built up crud (some that you can't even see) on the slides will adversely affect your plunging performance. I can only speak for the OF-1000, but on it, there is one long bolt with an allen head that limits the upward travel of the router motor. If you remove that bolt, the motor will easily separate from the base. I use Simichrome to polish the slide bars and then apply a bit of Teflon based spray lube on the bars and the sleeves (Boeshield T-9, Tri-Flo or Slick 50 OneLube interchangeably). Be very stingy with the lube and take a dry paper towel to the bars and wipe off as much as possible after application. I do this anytime I notice that the plunging action is not smooth as silk.