I have two custom fields in my database products_msrp and products_cost. I have them both in the Easy Populate config file as products_msrp,products_cost and they work just fine on import/export. The problem comes when I try to update my quantities in the database using a csv file with only the fields v_products_model and v_products_quantity. It will update the database quantity files just fine but it clears out my products_msrp and products_cost fields in the database.
If I remove the special fields from the Easy Populate config and upload my quantity update with Easy Populate it will leave my products_msrp and products_cost intact. I just have to remember when uploading my quantity update is to remove the special fields from Easy Populate config.