Suggest to add detail examples for "Interval " type date time calculation. The current Appendix H has examples for Duration and Difference, and they have been very helpful. However, in CQL language it's confusing for the implementers on how to treat/calculate the date time when it is "X starts 1 hour (day or week) before Y", since it's not obvious to the readers that they are not "DurationBetween", nor "DifferenceBetween", but rather "Interval".

For example, "X starts 1 hour or less before Y" logic in HQMF was using Duration concept. Therefore, 1 hour 59 minutes would still be considered as 1 hour and pass the logic. But in CQL, it is "Interval" and even 1 hour adding 1 minute or second would fail.
Similarly, "X 42 week or less before Y" is another ambiguous logic that we've seen in ePC02_CesareanBirth measure for date time calculation. if this logic is "DurationBetwen", 42 weeks and 6 days would pass, but since it's the "Interval", 42 weeks and 1 second would fail.

Adding "Interval" examples related to this type of logic would be very helpful.   

This is for page: https://cql.hl7.org/2020May/15-h-timeintervalcalculations.html