Is “Reward only for Results” too much to ask for?

When recruitment Agencies want a % of ANNUAL salary is it NOT Fair to expect their Service holds good for ONE YEAR?

Please do share your views – Do you Agree or DONOT agree

1 Recruiter MUST screen and send only qualified candidate    Match the requirement (not just pass any cv), in our case it is
   HK Resident, ASP.NET/C# coding skills, 3 to 5 years IT experience,    Salary range 25-30K per month
2 Upon Hire the candidate 40% (a % Fee based on Annual Salary)
3 Upon Completion of 3 months Probation 30%
4 Upon Complete 6months after hire balance 30%
5 Within 1 year if the candidate resign provide Free Replacement