So then you only need the nested loop to get and display the values needed from there and you’d do your calculation in the first loop.
if (have_rows('repeater_name')) {
while('have_rows'('repeater_name')) {
the_row();
$post_object = get_sub_field('post_object_field');
// get other field of row
// store to do calculation later
// or do it now
}
}