One word card collection

Q:

Salad bars that are served during certain hours are weighed by the scales installed at the cash register. I had doubts that such an object was placed. Does that mean that the object has the same weight as a plate? If so, you would have to place the object on the scale, zero the scale, then remove the object from the scale and weigh it.
Please answer what the object is intended to be placed.

A:

I am very sorry for the lack of notation here regarding the inquiry.
The scale for the salad bar at the cash register is set by subtracting the weight of 3 dishes so that it can measure up to 3 dishes at the same time from the viewpoint of cash register operation. Therefore, when using 1 or 2 plates, we will measure the weight of the plate. I am very sorry that this explanation is not enough. I have added an explanation to the scale at the cash register as shown in the attached photo. Thank you for your continued support.