Let me explain it again.
Before you could gate an action or lore recallwith a high DC and call it Very Hard or Impossible. The PC or NPC could attemptit but most woould fail. However you as the DM left the attempt unlocked.
This allowed PCs and NPCs wot use spells, tools, magic items, and allies to increase their chances or speed up a reroll.
Now, you have to lock the attmpt and gauge everytime the circumstances change, whether or not the attempt is uplocked.
Before: The evil wizard is working with a demon lord of a secret cult. Give my an 25 an I'll tell you the demon's name is Razmaztaz. Work Done.
Now: You put on a magic hat, does this unlock the Lore check? You took a long rest and swapped your skill profecieny to Arcana and History, does this unlock the Lore check? Mieky uses Help, does this unlock the Lore check? Louey cast's Enchance Ability on you, does this unlock the Lore check? You bring Gibgob the Sage, does this unlock the Lore check?