Is it working?

These numbers are measured, not estimated. They come from the same job records that charge credits, so a render that failed is counted here as a failure.

A failed render costs you nothing. If a generation does not come back, or our own quality check rejects it before you see it, the credit returns to your balance automatically.

Rendering goes down separately from everything else. When it does, signing in, your history and your balance all keep working — you just cannot start a new render.