You can also specify the readings at the top and bottom in the form.
This is normally used to determine the distance, but is used here to control the middle reading.
The average value of the top and bottom readings must be equal to the middle reading.
In the case of an entry, the difference between the two values is specified as a reading error and an average value is generated as the basis for calculation.
Reading errors can be localized by checking the corresponding column.
Example 2 is topologically identical to Example 1, except that the top and bottom readings have also been entered here.