Thank you all for your attempts to help.
special thanks to KBpsn for his informative reply.
I think I got it now so the ratchet and pawl are reversible, It appears from the AMM explanation that it has two cams and two pawls (each one is respective for a certain direction of rotation) and the switching between both is done by some internal gears based on the jackscrew torque, It makes sense this way.
I just could not understand the AMM explanation at first because it did not mention that the ratchet and pawl were reversible.
Thank you all once again.