Partial vs complete entries - viewing CSV file

Hello, another follow-up question to my post here from a few weeks ago.

When looking at the CSV export of entries, on a form using partial entries, that we are not manipulating via REST, it seems all partial entries are noted by having an ID in the column “Partial Entry ID.” However, in my previous linked post above, we determined that an entry that has in the column for “User Agent” just the string “API” means that this entry was added via AJAX and partial entries. So wouldn’t this then have a partial entry ID in the column for “Partial Entry ID?”

For the most part, partial entries clearly show a partial entry ID, the completion percentage in progress and progress *required fields, and also the User Agent used for that partial entry. However, we have some entries that show as user agent “API” and there is is not a Partial Entry ID, nor any percentage complete in the progress and progress *required fields. Would these entries be considered a full entry, where the user clicked the submit button, and are not to be considered a partial entry? It was my understanding that the user agent would read “API” if that entry was added by the partial entry feature.

In a nutshell, I’m looking for the easiest way to distinguish between a full/valid entry (where submit button is clicked) and a partial entry.