Windspeaker's Blessing question (Riot?)

Windspeaker's Blessing, in the mastery builder, says:

> Your heals and shields are 10% stronger. Additionally, your shields and heals on other allies increase their resistances by 15% for 3 seconds.

In-game, it says:

> Your shields and heals on allied champions (excluding yourself) are 10% stronger and increase your target's resistances by 15% for 3 seconds.

As you can see, the mastery shown in the mastery builder is useful for self-healing, but what is shown in-game leads to people being called bad names. Which is correct? It makes a huge difference for some champions, such as Tahm Kench and Darius.

Thanks!