how to format custom fields?

My services have been retained to finish up a project using the Directory plugin and CustomPress.

We need to format the output field by field, beyond the choices provided in the plugin of table, list, or div.

The site had 2 scripts in the default theme of the directory plugin:

single-listing.php
dr_listinglist.php

It appears that the only way I can format the custom field output is to modify one of your plugin's core files now which is core.php. That *feels* spooky to me because it will put my client at risk of not being able to update the plugin in the future.

Why aren't we able to influence output using the custom scripts that were in play before the most recent update?