There are 16 steps visible on the escalator at any one time.
The total number of steps on the escalator will of course also contain several in the flat step-on and step-off area as well as the hidden ones on the return route. Just how many are unseen will depend on the length and shape of the entire escalator path.
Going up, the human does 10 steps to the escalator's 6 = 16
Going down the human is brought up 6 steps for every 10 the human goes down = net result of 4 steps down for every 10 taken by the human. The human takes 40 steps down so that = (4 x 6) steps = 16