You Expertise please...

I Just got my 25k/Delta filled in Oct.
In November I correctly closed my MCI account & switched to Sprint for one month.

I now am going back to MCI for a second 25k.

Here's my question:

Should I try to get it again with the same Delta or should I use a United account number?

Do MCI (Computers) "remember" that the PHONE LINE earned 25k or do they "remember" the F-FLYER number earned the 25k?

P.S. (I realize that some of you do not condone this earning method, but I can live with it)

;->