IMUL Timestamps shall begin with the absolute time in the following format called an ASCII Timestamp.
@2021-01-03;01:02
After the absolute time has been specified, scripts may refer to the time delta in @minutes or @minutes:seconds format as follows:
@10
@20:30
The @10 means it's 10 minutes after @2021-01-03;01:02, which is @2021-01-03;01:12. The second time delta is 20 minutes and 30 seconds past @2021-01-03;01:12, which is @2021-01-03;01:32:30.