A: Youbooks uses various models form many providers on different parts of the workflow. When you enabled advanced mode, we either increase the reasoning budget or use a higher model (we experiment with both). Enabling advanced mode increases our bill significantly, so we have to charge a higher price on a per-credit basis (4x the normal price). The benefits are subjective and marginal. In general, we do not advise using advanced model model unless you have only one project and you don't plan on spending the remaining credits on other projects.