Is my height going to be less or more when measured on a stadiometer?

[estonianslayerr]

I got someone else to measure me using a book (placed ontop of my head), then using a pen to mark it next to the wall, finally using the measuring tape to see how high or tall the mark placed on the wall.

I got measured at 178.4, 178.5, 179, 179.2 cm, on 4 different attempts.

Evidently, based on this you could come to the conclusion that human error was evident in each marking here.

But, under a stadiometer is it likely to give me a taller or shorter height do you think?

For reference, this is what a stadiometer is - if you don't know:

 

[Arwin12]

depends on your posture but i would say shorter because you cant lay flat on a wall

 

[infinitebonemass]

from my experience shorter everytime i get mesured on a stadiometer i get a brutal reality check when i do it with the measure i get results around 1,78 but on a stadiometer i got 1,76