The "reading level" is the level required to easily understand the text. It is not indicative of text quality. For example, if your text is rated as "11th or 12th-grade student", it means that a typical student of that grade (or higher) will understand the text easily, while it could be difficult for students in lower grades to understand the text.
This tool is especially useful when you know your target demographic. It is based on the Dale-Chall readability formula.
The "reading time" is the time it would take an average person to read the text. On average, we can read 275 words per minute.
The "speaking time" is the time it would take an average person to read the text out loud. On average, we can speak 180 words per minute.