From the specification pdf, section "TimeParameters"

"A duration value can be obtained from the sum of setupTime, processingTime, validationTime and reworkTime."

For tooling, having to collect 4 separate values from users to calculate duration is somewhat cumbersome, it would be easier also for users to simplify this and provide a "duration" attribute in TimeParameters in cases they do not know or do not wish to have to specify four different time parameters. I do not think that a VendorExtension would be appropriate in this case..wdyt?

Thanks

It was in version prior to 0.3 like that and we decided to remove the duration in version 0.3 because it could the a source of inconsistency. You can always use the processing time as your duration equivalent.