When you have reversal material, the quality of the glass does impact the Dmax. More flare means lower Dmax. With negative material it would be Dmin that's affected.
Actually flare does not change the D-max or D-min of the film or paper, those are determined physically/chemically.
Flare does though change the qualities/usability of the image within that range.
Mark Barendt, Ignacio, CO
"The mind that opens to a new idea never returns to its original size." Albert Einstein