[BUG] Workflow Total Duration miscalculated when using a Delay step

**Describe the bug**
In order to implement a delay between two legs of a workflow I have, I had set up 2 different workflows with a delay between them, as advised by your docs. The sum of the total duration of the 2 workflows was ~2 seconds.

Recently you released the Delay step, so I merged the two workflows and added a Delay step between the two parts of the workflow. I didn't add any additional steps except for the Delay.

The Total Duration of the single workflow is ~8.5 seconds.

This leads me to believe something is wrong in how you calculate the duration of a workflow when it has a Delay step in it.

**To Reproduce**
Steps to reproduce the behavior:
I know that for me the repro steps were to compare the sum of durations of the two workflows against the single workflow that has a Delay in it. I ran the workflows multiple times to confirm it wasn't a glitch or an issue related to a 3rd party API. The duration results were consistent all the time.

**Expected behavior**
I expect a single workflow with a Delay to have a similar duration time, when compared to the sum of durations of two separate workflows, which contain the same steps.

**Screenshots**
N/A

**Desktop (please complete the following information):**
- OS: Windows
- Browser: Chrome

Thanks!