From edition Start of MapTiler Desktop, you can adjust the rendered zoom levels of your file. This article explains what is a zoom level and how to define the range of zoom levels in your project according to your needs. When you are processing a file, you define what zoom levels will be rendered.
By default, zoom levels are calculated based on the image resolution and its geolocation. There are min zoom and max zoom levels defined. With this information, you can calculate how many tiles will be rendered. You can find some further information on this matter in Tiles à la Google Maps article.
Changing zoom levels
The Start and Plus edition of MapTiler Desktop can process only one file at a time, that is why there is only one spinbox for min zoom and max zoom values.
Increasing max zoom by 1 or 2 zoom levels is available and preferred. Further increasing would result in a damaged image (over zoomed). When increasing the max zoom level, it is better to use the Cubic B-Spline resampling method from the Global settings.