Clarification on session duration format

[robogeek]

In the Session object there are two duration fields. The data type column simply says duration.

In https://github.com/AtlasPublicPolicy/charging-use-spec/blob/main/field-type-and-valid-entry-reference.md the format for duration is not discussed.

In another object, a duration field is described as a float(2) format.

Possibly the duration type is meant to be the ISO8601 Duration format.