Request primary assignment entry date use for cycle time calculations

[CBuckwal]

I've been asked to create a request report that captures the time from the request entry date to the first user assignment date. Will the primary assignment entry date reliably return that date? My initial testing looks like this is a valid field for what I want to calculate, but I wanted to double check here. 

I've reviewed the Tips and Tricks Calculated Fields https://experienceleague.adobe.com/en/docs/events/the-skill-exchange-recordings/workfront/apr2022/ca... and thought I could use the SLA section (around 8:15) in the video to create the entry date-first assignment calculation. But the video shows "User First Assigned" in the calculation and I'm not sure where that field comes from, since it's not a database field and if it's a calculated field, I missed how the field was created. 

Thanks for any insights on this.

Cathy

[CBuckwal]

Looking into this further, I find that I can't use the primary assignment entry date in a calculated field without a class casting error. I found the primary assignment entry date in an issue report, so I thought it could be used in a calculated field. The text mode for the issue primary assignment entry date field is below. Looking through the API Explorer got me more confused, since I couldn't find primaryAssignment:entryDate

displayname=
linkedname=primaryAssignment
namekey=view.relatedcolumn
namekeyargkey.0=primaryAssignment
namekeyargkey.1=entryDate
valuefield=primaryAssignment:entryDate
valueformat=atDate
 

I tried the following expression and received the class casting error.  

ROUND(WORKMINUTESDIFF({entryDate},{primaryAssignment}.{entryDate})/480,0)