Ah, I see, I read the relevant thread.
So: I do not plan to use 'extender accuracy' for throwables, in part because the system is incompatible with basic XCOM rules (max throw range is limited by unit's Strength, not by flat number; therefore accurate ranges and dropoffs should be too, else it makes zero sense). So, yes, the displayed number is pointless if someone doesn't use the new system.
(Explanation why it makes zero sense: that little number being displayed basically forces me to set all the new throw parameters for every single item in the game to keep consistency; nevermind the workdays required to do that, I would not be able to set any fair numbers because throw range is dynamic. So, I'm definitely in favor of classic XCOM rules here.)