I have never used chromogenic. I have seen it and prints change colour noticeably under different light. I thought it was Khaki and White instead of B&W. You also cannot push to get grain (I only shoot 4-5 rolls a year, but it's usually TX @ 800).
With chromagenics, you pull to get grain instead. IIRC. Most minilabs with reasonably modern equipment can push the "b+w effect" button to give you "true" b+w prints - I've had these once or twice, and while they're no substitute for a proper hand-prepared darkroom print, I haven't noticed any of the colour shifting you mention.
S
