Ok people I thought about this issue for a while, since it was bugging the crapp out of me. I will give you what I think constitutes a hard truth. This will work only for steroids with half lives of 5+ days.
Example: Bodybuilder 1: 1000mg of test for 5 weeks
Bodybuilder 2: (200,600,1000,600,200)mg(taper)
For simplicities sake let's say that the half-life of the test is 7 days. So after one week on test 50% of the test is gone from the system.
W1
START END
BB1: 1000mg 500mg
BB2: 200mg 100mg

W2
START END
BB1: 1500mg 750mg
BB2: 700mg 350mg

W3
START END
BB1: 1750mg 875mg
BB2: 1350mg 675mg

W4
START END
BB1: 1875mg 937.5mg
BB2: 1275mg 637.5mg

W4
START END
BB1: 1937.5mg 968.75mg
BB2: 837.5mg 418.75mg
So, at the end of the 5 weeks BB1 has a total of 968.75mg of active test in his system, while BB2 has 418.75mg of active test.

Now, for recovery
START W1 W2 W3
BB1: 968.75 434.375 217.1875 108.59375
BB2: 418.75 209.375 108.59375 Recovery begins

So, mathematically speaking bodybuilder 1 will take 3 weeks after his cycle starts to clear test to acceptable levels, so that natural test can recover.
Bodybuilder 2 will take only 2 weeks to have the test clear his system.

So, for all you supporters of the taper theory, please bear in mind that BB1 took 5000mg of active steroid Vs. only 2600mg for BB2. The rationale here is that BB1 will not lose all the added mas gained in just the last week of exogeneous test clearance. Therefore in this case, taper theory is not very good.