PSF's tend to be poorly cooled, rarely filtered, and rarely changed. I would step up to a full synthetic ATF that mentions DexronIII or Mercon on the bottle.
If you are cheap, I would minimally use a MerconV.
Someone mentioned that Nissan switched to DexronVI in their PSF's. Hopefully, Toyota will do the same. An easy to find store bought ATF is better then some silly dealer-only poor-performing PSF.