I hope my point in describing them was not too subtle.Thanks for incident info!
The standard MOD limits are very safe, and it takes time, often significant time, at the depth of the MOD violation to cause a toxic event. Toxicity is a real concern for technical divers because they are capable of making very serious mistakes leading to major violations for length periods of time.
In contrast, NDL divers are highly unlikely to have such serious violations. That does not give you permission to violate those norms. For NDL diving, I will normally stay within the 1.4 limit throughout the dive, but I will not hesitate to spend a few minutes of a dive within the 1.6 limits. In those cases, I know before the start of the dive that I am going to do that--it is not a result of not paying attention to my depth.