Delta checks

[BEHAL]

Requirement 3.5.3 z) states :

z) For a delta check, the delta value shall be calculated as the difference between the reference value and the check parameter and supports both positive and negative deltas

Why is it said that the delta value supports both positive and negative deltas ? Do you mean that it is the absolute value of the difference between the reference and the check parameter value that should be taken into account and evaluated against the thresholds ?

Furthermore, requirement z) indicates that the delta value is calculated as the "difference between the reference value and the check parameter" whereas requirement aa) states that it is "the arithmetic difference between the parameter value and the reference value".

Can you clarify and hamonize if needed ?