It's because the nightfall is level 32. Meaning you don't get a level advantage being higher than 32. Enemies get level advantages, we don't.

This is why I hate scrubs that post "Must be level 30+ in VoG Normal" "Must be level 32 in Crota NM" All light level does is allow you to do the maximum damage you should do against equivalent level monsters or lower. A level 28 Player and a level 34 player with 300 attack weapons will do the exact same damage and die just as quick as one another in VoG normal. That's why as you level up, lower level monsters kill you just as quickly, otherwise you should be able to stand in a pack of monsters for an hour and not die. When a Level 32 player reaches level 33, he's not doing More Damage to the Level 33 monsters now, The Damage Reduction modifier has been removed and you now do the full 100% damage you should do, so ya technically *you do, do more damage* but it's because of Leveling Strength, as the under leveled damage modifiers are being removed. This is also why Attack Levels come in increments of 10, except recently which is kind of stupid. -300 Attack Weapons were for when the level cap was 30. -10 Attack Per Level -A 28 should have a 280 attack weapon to do 100% damage to level 28's. -331 Attack Weapons were for TBD, because Crota has a 33 HM, though Crota i do believe is 34. Which is why HM Crota got even easier, now that people can match Crota's 34 and reach 340 Attack, allowing them to do the max allowable damage to him, that wasn't previously reachable. -365 Attack Weapons are for god who knows? I'd much rather it had stopped at 348-360, only if they make the Boss of PoE 35 a 36 Boss would it make any sense, but then again, it still wouldn't make much. We used 331's vs 34 Crota and then After HoW came out, we finally get the ability to fight him at his max level ---The 365 Attack is useless and makes it so that everyone can easily attain the max attack weapon damage they need to do 100% to all the enemies in the game quickly, even the Bosses and PoE 35, etc... On my old Exotics that I leveled up or were almost maxed, instead of leveling them from 322/331 to 331/331 by using an exotic shard, I just take the Exotic Shard and Ascend it straight to 354/365 and save that last nodes exotic shard, since their would be no bonus from the extra attack. I think they just got lazy and didn't think out the math or mechanics of the game. I don't like that all the Vault weapons can reach 365, making them the obvious best items. I don't like that Vex no longer has the minor attack penalty of 323 and now is simply 365 like all others. I'd much rather they made it so ascension works for one expansion pack worth of upgrading. -VoG weapons -- 300 to 331 -TBD weapons -- 331 to 348/360 Range -Vex Mythoclast - 323 to 343/348 Range

Being a level higher than an enemy does not make damage increase. A 32 and 34 with the same gun, shooting a level 32 enemy will deal the same amount of damage. Only when you are a level lower or more does damage get affected and that's a debuff in damage.