First off for those that read the Tech paper - while it isn't made real clear in the publication - there is a distinct difference in operating systems between Electrohydraulic (EH) versus hydraulic (H) transmissions.
Torque converter controls on the EH allow for clutch modulation which controls slippage from near zero to 60 rpm where the H units do not provide slippage by design. As for actual clutch actuation the same thing applies. EH units monitor and control clutch slippage on the gear change and after. H units apply the clutch but do not provide slippage by design. Friction material did not go through any design or material changes during these fluid tests. As a result control systems did not change either. In short what that means is you will not get any issue going from ATF 3 to 4 on the H transmissions at idle or down the road. H units are 30/31TH fwd, 904/998/999, 727, 42/44/46/47/48 red units.
RFE units fall under EH as do 41,42,62 FWD trans. For guys using the H rwd units note in the pub that using 4 greatly reduces wear - and on the OD units, there are light years differences betweeen dexron and 4 regarding wear.
As for cold fluid viscosity - 4 is the best of the fluids ever used by Chrysler. Reference to "wax". Dennis and Tracey (female) were both sharp cookies. Dennis retired and Tracey left Chrysler for a job at another company - at a great loss to Chrysler.