Pure metagaming, Chai. He will understand he can't add a "bear" enchantment to a "bear" enchantment to make it a "two times bear" enchantment in strength, But maybe doing so will end up with a stronger "bear" enchantment. Such then to keep things ordered in his mind, he'll now call it a "brown bear" and a "grizzly bear" enchantment. DMs only tell players + values because the player understands those a LOT easier.
The DM doesn't have to tell you a thing, honestly. "yeap, you are very darn certain it is sharper than before. In fact you proved it by cutting through a rock like butter." Vs. telling you "it is now a +10."
Mohs scale in mineral reference to numbers is a perfect example of this. But anyway,
/end tangent. Back to the nerf frustration.