Referral credit discrepency

[Daniel655]

Hi,

I wonder if anyone knows about this or can explain this.

Airbnb is promoting me to "refer a friend"

i have my own referral link and when viewed it shows this.

Daniel gave you $38 to travel

Airbnb is the best way to rent unique, local accommodations on any travel budget. Get $38 off your first trip of $71 or more.

as well as:

Share your love of travel

When a friend travels on Airbnb, you get $22 in travel credit

So I have used this to refer a friend and she saw the exact same thing. namely get $38 off.

However after completing her regristration it only shows $25 credit in her account.

and instead of the $22 its only $15 for me.

Why is there a discrepency with what is shown and whats actually being given?