Comparing several FIT files (Race 2 and Vertical) this is “The IA summary”
Summary of detected behavior
In activities with pauses and repeated segments:
The Vertical prioritizes raw accuracy: if you move, it counts it. If there's a curve, it tries to follow the path you took.
The Race 2 prioritizes track clarity: it prefers to trim the track slightly (14.12 km) to avoid GPS noise giving you an inaccurate distance reading, especially after a pause or in areas you've already traversed.
Final Verdict of your comparison: The Suunto Vertical performed like a precision "tank": there's hardly any error between ascent and descent, and it doesn't hesitate to count every meter you move, even during pauses.
The Suunto Race 2 is an "optimizer": its priority is that the track on the map looks perfect and without spikes, so when in doubt (during pauses or sharp turns), it prefers not to add distance.