What does the reward panel mean by 15% grind boost

[2501]

Someone please help me understand this...we already have a 10% grind boost for 3 weeks, so if we get the 15% grind boost for 3 weeks do we have a total of 25%? Please someone shed some light on this matter.:confused:

[Halcyote]

no it just means it'll be 15% instead of 10%

[shiningflare]

You will just have the 15% boost instead of a 10% boost (if they unlock it).

[Earthbound Ranboob]

I hope it unlocks. I have a ton of stuff to break.