Porfolio: Just show me actual Sprint assignments from Jira

[Jeremy Tipton]

I'm running a trial of Portfolio for Jira Cloud, and I like the UI and many pieces of the organizational tools. But I'm not yet looking to blindly "Calculate" our sprint planning.

I need to start by seeing in the timeline all the issues as they have actually been assigned Sprint values on existing Jira tickets. Is that what Portfolio does, and then sprinkles some extra tickets from the backlog "scope" into existing and future sprints?

I see on https://confluence.atlassian.com/jiraportfoliocloud/assigning-issues-to-sprints-828785264.html that sprint assignment in the timeline only works "For issues that are not already assigned to that sprint." So does that mean that issues that are in fact assigned to a Sprint in Jira will display in that sprint column in the Portfolio timeline, in addition to all the "calculated" other sprint assignments?

If Portfolio disregards the Sprint assignments our teams have deliberately made within Jira, then Portfolio is 100% useless to us. We mostly just need a way to visualize all the plans we've already made, without doing double-data entry in some system outside of Atlassian. 

So thanks in advance for clarifying the behavior regarding Sprint assignments from Jira to Porfolio for Cloud!