Kim, the development times suggested in the Kodak literature are for negatives that are to be printed with enlargers that have a diffusion light source. Negatives that are to be printed with an enlarger that has a condenser light source require a less dense negative, and so Kodak recommends 20% less development time than what is listed in their tables. I have found their recommendeed times are right on the money for diffusion light source enlargers.(posted 8782 days ago)Your best option, if your current negatives print OK, is to adjust the development time with XTOL to the same extent (%) as you have diverged from the Kodak recomended time for D76.
Eilert Anders