There are differences in Tow/Haul depending on model year.
I would have to go back and see but if memory serves me - one year T/H disabled OD and then later T/H would change the shift schedule to allow OD if certain vehicle parameters were met like vehicle speed versus engine speed.

Also - pulses per mile - i would have to check on that too - 44000 come to mind but it has been years since I worked the logic side of these things. Count the annulus lugs in the overdrive - the part that the park pawl engages (same lugs that the speed sensor senses) and then multiply that time revolutions per mile based on a given prop shaft speed. Also, the 727 and all Chrysler Rear Wheel Drive units operate ALL the same in regards to 1-2, 2-3 and 3-2 and 2-1 shifts. The fight between governor pressure and throttle pressure determines what happens. You can get a 3-2 down shift if you have steady state throttle while the vehicle starts to slow (slowing reduces gov. pressure). Normally closed throttle downshifts result in a 3-1 - yes, but it is not "designed" this way. A sticky throttle valve in the valve body can/will result in a 3-2, 2-1 dhown shift. Lockup on all the old RWD units are controlled by electronics except the very early units. With a lock up solenoid - the solenoid closes, pressure builds behind the LU valve and shuttles it over to acheive LU. When we command no LU, we shut this solenoid off and you get open converter control - no LU.