@Wizofoz
OK, but if you're using Assumed Temperature/Flex (only), then your VMCs should be based on Max Rated, which means you shouldn't be concerned about invalidating those speeds if you select TOGA, surely ... though I expect JT and OS to chip in here that any thrust increase in such conditions should be applied with caution, whatever the theoretical VMCs.... the FCTM quote seems to suggest you get extra thrust with TOGA, i.e. you change the rating, not just the actual thrust.
Using the term "Derated" for a takeoff where the rated thrust is not in fact changed seems a little bit perverse on Boeing's part.