That still means they have more confidence in umpire's original decision isnt it?
Or alternatively put, it means they claim - umpires original decision has lower error rate compared to DRS if ball is hitting stumps by less than 50% and higher error rate (compared to DRS) if ball is hitting stumps by more than 50%?
Doesn't make sense to me or I am missing something.
It’s nothing to do with confidence.
Basic rule of cricket is that the umpires decision stands - you can’t argue with him on a Saturday for example.
The technology is there to support and not undermine this system. It allows the umpires some tolerance because there is always doubt with a human decision.
If the standing umpire deems it out - the technology has to PROVE CATEGORICALLY he is wrong. The technology cannot do that with 100% certainty. Ergo the margin of error is built into the DRS system.
It’s the same as confidence limits in statistical analysis, and tolerances on calibrations etc.
Also, if you remove umpires call you might as well remove umpires entirely, and the game would be over in 2.5 days - great to watch and for all involved 👌