How to update rows in a repeater?

In the Pro Form, Update Post Meta options, there’s Update Row.

I’m using ACF as the source, and I’m using the bricks native query loop to go display repeater rows. Inside of this query loop is a BF quantity field, with ID set as quantity_{brf_loop_index:1} like the docu says to do for ACF.

Anyway, in the Post Meta Data, on the form options, I set:
Is Repeater Field: True
Repeater Action: Update Row
Post Meta Name: item
Field key:

All Rows: True

Row Fields
Name: quantity
Value: quantity_{brf_loop_index:1}

When submitting the form on the frontend it changes all fields to the same value. Is it possible to loop through each one and update it this way? I know it can be done with the BF repeater form element, but I’m wondering about doing it this way too, because I want to display a bunch of other data in non-field format without having to override a bunch of CSS.