Tooltip not displaying correctly?

Hello, i am playing a Templar self cast frostbolt build. i am level 81 ( on xbox) and my tooltip DPS for a 5L frostbolt setup was 42K. i recently acquired a helmet with a +40% frostbolt damage enchantment and when i equipped it, my DPS only went up around 1K.

Is the tooltip not displaying this increase in damage? i also notice it when i get items that add projectile damage