Two or more operations may be comparable as long as there is no economic difference between them that can affect the price of a good or service.
Jose Molina Calderon's article in Prensalibre.com reports that "for the purposes of determining a price or amount that can be agreed between independent parties in comparable transactions in conditions of free competition as referred to in Chapter VI of the Tax Update Law (LAT by its initials in Spanish), comparing the conditions of transactions between related persons other comparable transactions between independent parties.