Problems about billing process

I am a developer and i am using api functions to retrive data, as i can see every time you make a query you have to pay the query cost, but in case of error message it’s strange the fact that i have to pay for visualizing an error response. Any information about this? thanks in advance.

The costs are intended to be reflective of the server utilization that any request consumes. When a “failed” request is made (no result found, unknown identifier, etc) the request has still consumed server capacity to perform that lookup. Additionally, having a non-zero cost for such requests encourages users with an incentive to strive to not make unnecessarily wasteful requests. If there were no cost, a user might repeatedly poll the status for a flight identifier hundreds of times per second waiting for its visibility in the system.