FCU’s Affiliate Program is based on what Commission Structure?

Each freelance site’s [FS’s] affiliate program [AP] [and obviously other site’s APs], have commonly their own AP commission structure. Some sites pay money for the number of impressions that are generated by the Legit Traffic sent by their affiliate partners: some others pay a percentage of the fee that they charge from their users and just like this, there are other commission structures too.

FCU [Freelancer.co.uk] is a new FL and is offering an affiliate program in which anyone can participate. I have joined this AP few months back and have earned little money too. But I do not know exactly on what criteria, does FCU affiliate commission is based on.

Let me explain with my own affiliate stats example:

First of all, I can see two rows in my stats. One says Free Sign Ups and the other one says Paid Sign ups. This does sound like a simple AP commission structure where we can earn money when someone who we refer signs up at FCU.

But I am little confused about the amount of money that I earned when I first got to see free and paid sign ups in my AP stats.

Commonly, when a person signs up [for free], I saw £0.25 being credited to my account. Sometimes, I have seen £0.75 being added to my account for a paid sign up. So I thought that these are the rates that we will get for paid and free sign ups. But the strange thing is that, I sometimes earn £1.00 for a free sign up and sometimes, £0.25 for a paid signup.

I am not sure exactly what money FCU pays for the sign ups, but normally, you can expect to earn £0.25 to £1.00 per signup.