DI plans to introduce a new condition-monitoring variable type named LifeTimeVariableType which provides properties which allow for a high degree of flexibility to monitor the remaining lifetime of a resource such as device or component.
https://mantis.opcfoundation.org/view.php?id=8047
PA-DIM defined the ResidualVitality property which serves semantically congruent properties.

• The value of PADIM.ResidualVitality provides an "normalized" indication between 1 = 100% -> full vitality and 0 = 0% -> no vitality
• The value of DI.LifeTimeVariable provides a "non-normalized" indication DI.LifeTimeVariable.StartValue down to DI.LifeTimeVariable.LimitValue

Assuming a linear relationship they can be mapped onto each other by:
PADIM.ResidualVitality = (DI.LifeTimeVariable - DI.LifeTimeVariable.LimitValue) / (DI.LifeTimeVariable.StartValue - DI.LifeTimeVariable.LimitValue)

Considering the very close semantic relationship of the two condition-monitoring variables I would propose, to reference the definitions within the specification documents to each other and shortly describe their relationship.
Maybe an example could illustrate the parallel usage of this "normalized" and "non-normalized" condition monitoring indicators.