it works like this.

if the hirer put salary 2000 - 3000

and your expected salary is 2000, then you will see 'around expected salary'

if you put 1800, you will see 'above expected'

if you put 3200, you will see 'below expected'

the concept is depends on what range the hirer put (max range is 2x)

as long as your salary fall into range, then you will see 'around expected salary'

but i'm not 100% sure, I only recall using my memory.