I've observed the following with IDF editor which may require a minor fix.
AvailabilityManager:OptimumStart is not listed in the list of selectable object types under AvailabilityManagerAssignmentList. I understand that it should be one of the options, based on the the documentation and usage in the example file 'OptimalStart_RefBldgLargeOfficeNew2004_Chicago.idf'.
The IDF runs fine once it's typed in, but it was a slightly confusing when IDF editor didn't provide it as a selectable option and highlighted it as an invalid input when I typed it in.
Kind Regards
Benson