Very Fresh Clothing moodlet (which was +25 for Normal cycle) is for whenever you upgrade your washing machine (or possibly use more expensive models?).
This moodlet improves to +32 for Delicate cycle and lasts for "2 days" (tested on an upgraded Rahul Josher Washer). This may actually be slightly more than 1 day, given the game's tendency to display times rounded off.
It's interesting to note that the benefit appears immediately after the WASH cycle is complete. You don't even have to put them in the dryer!
Basically, the washers do the usual exchange of "more time spent, better moodlet gained," with this improving through upgrades.
(This thread is a bit old, but it's also the first hit on Google searching for "sims 3 set wash type" so still relevant I guess...)