They are definitely modifying the dice rolls in some way in tactician and honor modes. You can see it in things like ability checks. Normally you’ll have a chance to roll well for any roll even if you don’t have proficiency in the skill, for example a 15 CHA dialog check and you have 8 CHA, if you roll a 16+ you’ll pass it. On tactician and honor mode if you don’t have proficiency you’ll struggle to pass the check, all your rolls will be under 5 usually. I’ve burned 4 inspirations with advantage before and watched 8 dice rolls under 5 for a skill check I wasn’t proficient in multiple times in a run. I just ignore it now since it is what it is but I really wish the difficulty wasn’t rigged like that. It’d be great to have a fair but brutal mode.