Nami W (heal) on allies heals for way less than indicated on Howling Abyss [GAMEPLAY]

I recently played an ARAM as Nami and found that her w when used on other allied champions healed for much less than the ability tool tip indicated. When used on herself, however, the correct amount is healed. Is her heal on allies weaker than on herself? I have played her before and perhaps this is a change to her but it was not so and she would heal others for the full amount listed.