Pull ‘backup’ fields?

Hello is it possible for this plugin, or will google allow, that if a simple product has a custom field, it can be used to populate a required attribute (e.g. a pickup SLA). BUT then if a variable product has variations with different attributes, can it use a custom field that is set up for the variation, as a ‘backup’?

E.g. I use field mapping to set pickup SLA to grab a custom field value on a simple product (just an example).

Then I use field mapping again (2nd line, repeat) to set pickup SLA to crab a custom field on a product variation.

Would the second field mapping line act as a ‘backup’ to the first field mapping line? So, if they are designated to fill in the same info, but from two fields, in case one is empty?

Then that way we could have simple products and variation products with specific attributes?

Is this possible?