I’m not quite picturing your requirement, but I did have something a couple years ago that sounds similar.
My field is in a Field Editor, on a single/new-record model. (The field editor is in a popup; the action steps before showing the popup include a Create Row.)
There are two iterations* of the field (which is a Number datatype). One is a Required field, rendered when the model has no data rows. The other iteration is not required and is rendered when the model does have data rows. As the user interacts with the field, the two iterations are toggled. The Required attribute also prevents the blanks. At least, this is how I recall it working. I would need to do a little testing to refresh the memory, but maybe that’s idea enough to get you going a little farther.
- Iterations, or occurrences. One field is placed under the other; only one at a time is displayed, according to the rendering rules.
