Blitting DIB sections

I'm working on a program that performs a lot of manipulation on a 16 bit non-palletized DIBSection and then blits the result to the screen using BitBlt. If the screen depth is 16 bits, everything works perfectly. If I set the screen depth to 24 bits, then the display is messed up with wrong colors and fringing.

Isn't BitBlt supposed to handle color translation from one color depth to another? I could understant dome strangeness if the screen had less color depth than the bitmap, but it doesn't make sense to me that everything gets messed up when it has more.

I have always done this with 32 bit BGRA DIBSections and it has always worked blitting to 32 bit or less screen depths.