Different doctors may have different opinions on same input. That is why there are guidelines. Doctors are service providers as well, I doubt someone would refuse you doing a PFO test if you asked for it but again if a doctor advises you for a closure without you ever being diagnosed with DCS I would think this is out of guidelines and I would immediately get a second or third opinion.I don't try to prevent anything. The doctor does if he thinks there is a need.
The benefits of prevention are significant only in the case of mandatory accelerated deco diving. The DAN guidelines are for rec divers (they cite studies about recreational diving).
Technical diving is also recreational diving, unless you are a commercial diver that is. Where exactly you see that they are excluded in this report? Traditionally DAN includes all type of divers in their reports.
Anyway I recommend you have a look at this post.