What is the optimal operational aces range for this model?

I've been reading a few different manuals, and I'm really confused about the recommended operational aces range for the XYZ-500 unit. Some sources suggest a minimum of 10 meters, while others seem to imply that the performance degrades significantly below 15 meters. I'm planning to use this device in a semi-enclosed area, so I need to know if I should be concerned about the lower end of the spectrum. Has anyone here had real-world experience testing this in confined spaces? Any advice on calibration or settings adjustments would be greatly appreciated.