centering in Mplus

#1
Dear all,

I try to center my variables before conducting mediation analyses using the following code under DEFINE:
CENTER BDIBAS (GRANDMEAN);
CENTER BDIm6 (GRANDMEAN);

When I check the results, the mean of the first variable BDIbas has become zero (instead of 34), but the mean of BDIm6 is .45 (instead of 22). I do not understand why BDIm6 hasn't been totally centered to zero.

Does anyone have a clue and can help me out here?

Many thanks in advance, Emma