I just did a fluid exchange this past weekend on my 2005 Civic. This is the generation of Civics that had the high incidence of faulty auto transmissions, but apparently after they fixed whatever the problem was (I think the story I find most believable is that the clutch packs were made of a cheap material that would break away and clog lines or the pump in the transmission, leading to inadequate lubrication).
I also had an aftermarket transmission cooler installed at the same time. Maybe I'm going overboard on the preventative maintenance here, but I almost own this car outright, and it's got under 50,000 miles. I'm a huge fan of not having a car payment, and I'd like to do so for a very long time. (I also use RP 5w20 and Wix or PureOne filters.)
I unplugged the negative terminal of the battery for about a half hour after I had the fluid exchanged. (I insisted my mechanic not say the word "flush" and "transmission" in the same sentence. This was the service where a fluid exchanger collects old fluid pumped by the transmissions' own pump while putting in new fluid until all is clear). Theoretically this cleared all the information that the car used to determine when to shift. I think it takes 50 miles or so for the car to re-determine shift points and other ECU data, but I'm not certain that's right.
I honestly haven't noticed any real difference in the way the car drives or the fuel economy readout on my UltraGauge since doing this service. I've driven it about 150 miles since (so 50ish re-setting the ECU and TCU, and 100 since they recalibrated themselves?)
I still feel better about having all DW-1 vs. half & half in the transmission & torque converter, because I read in a forum somewhere that the DW-1 has less friction modifiers and therefore is less likely to lead to the kind of issues that the Z-1 might, even though mine was serviced regularly (3 drain & fills in 45,000 miles) and was perfectly clean, smelled like new, and always left very minimal gunk on the magnetic drain plug.
Maybe I am drinking the Honda Corporation's Kool-Aid, but I'd be afraid to use any non-Honda fluid in my Transmission. I think the Honda design is unique and far less robust than their manual transmissions. Pair that with the decline in quality Hondas have undergone since they were basically solid tanks in the 80's and early 90's, and I'm not willing to take the chance, despite several pieces of anecdotal evidence that MaxLife ATF or Castrol work fine and don't cause our transmissions to blow up.