Healing Wave vs Healing Surge?

Ive been playing Rsham for years and I just now noticed that they both heal for the same amount. Outside of mana cost and cast time, is there a significant difference…oh, and the Primordial Wave/Healing Wave spread.

healing wave : 3% mana , 455% heal, 2.5sec
healing surge : 10% mana , 408% heal, 1.5 sec

healing surge is getting buffed to support the new tank changes and spot healing