Though the explanations for how processors and acquirers compensate independent sales organizations and agents may appear straightforward, "the devil is in the details of the arrangement," says Adam Atlas, a Montreal-based attorney with Adam Atlas Attorney at Law. A contract may call for the processor to pay an ISO 50% of the net revenue the processor earns for each merchant the ISO attains as a client. "What does net revenue mean?" asks Atlas. "That will be unique for every single contract," and the pertinent definitions may not be spelled out, he adds. For example, a processor may subtract different expenses from the merchant revenue and give the ISO a percentage of the remaining funds. "I am an advocate for being very clear in contracts as to who is getting paid what," says Atlas. "There are many reasons why contracts are not specific as to what net revenue means."