As per the threads here, the answer is NO.

To rephrase, for example, Million Miler status on United gives you lifetime Premier Executive (50,000) status. If you are a MM and want to achieve 1K, must you fly the entire 100,000, or just 50,000 (the difference between Premier Executive, which you are guaranteed, and 1K). The answer is the whole 100,000.

This applies with every airline. Including Delta. Of course, if you have lifetime top-tier (TWA for a million miler or CO based on discontinuted program--see CO board) this point is moot.

Similarly, Centurion Black card holders get free mid-tier status in a variety of airlines. It is my understanding that they must still fly 100,000 to achieve the top level. For example, they get free Gold Medallion status on Delta Air Lines. But if they want Platinum, they must fly the entire 100,000 miles, not just 50 (the difference between GOLd and Platinum).

BizJet