Paul, i appreciate your confusion as i recently joined the Anova Facebook group where i have read with utter amazement at the extremely misinformed recommended times and temperature for the same cut of meat, not to mention food safety matters. Particularly alarming is the resistance and push-back to correct information. I understand that subjective personal preferences account for some variations and they always will.
You asked about degrees of tenderness and yes, meat can be much more tender after 16 hours than 3. There's a dramatic visual showing the impact of cooking time at the following site which can be trusted for its proven accurate information:
My first piece of advice to you is to always consider the source of your information and if it can be trusted. The amount of incorrect information available far outweighs the correct. I am not at all surprised by your experience. Trust your best judgement, - along with Lopez-Alt and Baldwin.
When confronted by a wide range of details it has been my practice to never consider the extremes in any matter.
I am familiar with "Kalb falsches filet", however here in NA it's most frequently sliced émence for veal cutlets. It is considered a "tender meat" because of the young age of its previous owner. We in NA have a significant challenge with the inconsistent terminology applied to cuts of meat. In most cases a cut of meat that in NA is generally called the long loin ( or the short loin and sirloin, - see what i mean? ) and the rib section are considered to be tender.
I am certain there will be current Swiss books on SV as the cooking technique started in Europe, so you folks have had a longer time to get it right. In addition to Baldwin, you might refer to "La Cuisson Sous-Vide" by Georges Pralus, the father of SV. It was the basic guide used by European chefs to implement the technique a dozen years ago or more. I would trust contemporary information such as the more recent practical work by Nathan Myhrvold.
Agreed that chefs have an advantage over the home cook, mostly in their culinary knowledge and experience which enables better judgement. I frequently recommend Community members maintain a SV cooking log detailing every cooking experience with outcomes and recommended adjustments for their future guidance. By employing a log my objective is to become an ever-better SV cook. Try it, you might find it useful for your personal success.