Mobile and landline destinations often have different call rates due to the fact that they belong to a different network operator. Local carriers set rates for their own networks. That is why the rates section in the Yolla app shows the rate as starting from a specific amount and up to a specific amount of minutes.
You can see the exact rate each time you make a call when you dial a phone number (Keypad), or when you choose a contact’s phone number (Contacts).