A couple of years ago, I was pondering the same question so I did some research. I lost the exact numbers in a hard drive crash but maybe this will help some.
1. Most affiliates of a program thinks of a 50/50 split as a true 50% of gross. So if the subscription is $30 then they are expecting $15
2. If you advertise 50/50 and pay them on gross net of processing then you would be paying about 42.5% of gross.
3. You could advertise a 60/40 split and hide the fact that you are going to pay based on gross less processing and in dollars be at about the same amount as a true 50/50 split.
If I could give you the numbers, it would amaze you at how many choose the third approach. I chose to do number 1. I rather pay the extra $2.17 to my affiliates and never have my honesty questioned. Further, I consider my affiliates true partners and treat them equally. For example, lets say Mr Big Link List says I will promote your sites if you will pay 60% of gross. If I agreed to his terms, I would immediately charge my webmasters' site to say "we pay everyone a true 60% of gross".
I reread this reply and it smells like a can of
.