The art & science of asking questions is the the source of all knowledge" - Thomas Berger

I discovered that my Hennsley™ mattress has a slight deviation on the length and width as compared to the size given to me. Why is this so?

Hennsley™ mattress has a dimension size tolerance of ± 2cm in width and length. Mattresses are not produced out of a mould.  Manpower is needed to sew and French-up the whole mattress, thus there will be a possibility of slight deviation in sizes.