The fastest way to spot an honest astrology tool is to ask it what's math and what's opinion. Here that line is drawn on purpose, in the architecture, not just the copy.
Calculated
Positions of the planets, the degrees between them, your rising sign, your houses, your BaZi pillars, your Human Design gates. These are astronomy and arithmetic. They are either right or wrong, and the Engine gets them right to a fraction of a degree — including the boring, easy-to-fudge parts like historical daylight-saving rules for the exact place and date you were born.
Interpreted
What any of it means. That a tight Mars–Mercury square makes your thinking combative, that a Convergence across three systems is worth trusting — that's reading, and Bob will always sound like he's reading, not reciting a law of physics. When he's less sure, he says so.
Calculated
"Your Mars is at 14° Leo, square Mercury at 16° Scorpio, orb 2°."
Interpreted
"So your mind comes in swinging — that's the square talking. Useful in a fight, expensive at dinner."
Everywhere a reading leans on a number, you can ask to see the number. It's in the data tables under every reading, and it's never hidden behind the metaphor.