Thank you for the feedback. If there, in fact, is a difference between losing dexterity vs. ignoring dexterity vs. denying dexterity, then I would read that sneak attack can only be performed in the following situations:
- against unaware opponents, which includes surprised opponents
- against flat-footed opponents
- against helpless and pinned opponents
- against opponents the sneak attacker flanks
As far as invisible attackers, and blinded/cowering/stunned defenders, the defenders "loses" dexterity, but does not necessarily suffer from the conditions above. Flat-footed also "loses" dexterity according to the combat modifier table and the appendix, but the actual entry, which trumps tables and appendices, states the defender "can't use" their dexterity, so that puts in into the group above, I suppose?
I feel like I'm splitting hairs, but I can't ignore that, after several printings and errata, "loses" and "is denied" area still listed separately as though they should be considered two separate conditions.