True, human loading in burst firing mission would not fall far behind autoloaders even for 155mms seeing that 120mms load faster than autoloaders on a fresh crew. Autoloaders only matter more in the longer run and that isn't even considering the maintenance complexity and time required for the autoloader in field conditions.2. I agree it’s a tight timeframe, but I can also guarantee that loading isn’t the limiting factor. You seem to be very hung up on that.
Strategic mobility also matters as the PCL-181s are designed to be air mobile. The addition of an autoloader will require an even stronger and likely heavier chassis for the PCL-181 or reduce its current ammo capacity.
In the end the PCL-181 was designed to replaced towed howitzers and not the SPG for armoured formations which the PLA has the PLZ-05 for, which has all the bells and whistles you are asking for.