Hvergerthi, I hope you are kidding! I have only heard of such advice from the pharmaceutical industry!
Everyone knows calcium is an essential mineral and anyone with a little knowledge about mineral ratios knows that calcium and magnesium work hand in hand at a 2:1 ratio !
I think you should read these posts a little closer, ascorbic acid is ascorbate acid its not an ascorbate or buffered with anything!
I hope no one takes this harmful advice seriously!