Software Testing Estimation

Estimation on Testing effort is always an interesting tophic. Testing Estimation depends upon the development estimation. Mostly I didn't see any separate estimation for testing (test execution activity). Always it is used to be assumed that testing should be completed within 3-4 builds once the feature is fully implemented. I know people are following different estimation techniques. All are based on their experience (see blog - pagkils).

Few of the known models are,
1. COCOMO Model
2. FP (Function Point) Analysis
3. WBS (Work Break-down Structure)

Last year, I had a different situation with my previous manager. Our application is a web based project and always the changes will be in existing functionalities. We had a tough time for Automation also. One day he said that fresher should execute 40-50 testcases per day. QA Engineer (whoever having 1-3 years experience) should execute twice the amount of a fresher. Senior QA Engineer (whoever having 4-6 years experience) should execute twice the amount of a QA engineer. None of them agreed this except freshers. Do you agree? Any comments?