Profile For Frank Da Tank

Hey guys, I hope ya'll are having an amazing day. I just have a quick question or seek advice if anyone can help me out. Can a driver interchange his SLEEPER BERTH hours with OFF DUTY hours? Even if his vehicle IS equipped with a "sleeper berth", would there be an issue with a DOT Auditor or during a roadside inspection if a driver takes all of his resting hours in OFF DUTY as opposed to SLEEPER BERTH? If so, can I get some information of penalties or violations that can result due to this or maybe can I see some sort of proof that sates this might be wrong? My co-worker that showed me his logs since Janurary and it threw me off that he hasn't been using SB and I've tried doing some research to answer this but no luck.

As I'm still trying to understand PC, I came across this website that states this as an example on how to use PC, but on the other hand I noticed the FMCSA Website (Question 6) states the contrary. Would anyone happen to know if this example is valid?

Thank you all for the kind replies, you all have been very helpful!

I need a little bit more assitance trying to understand the AG Exemption, for example; If my terminal and load are within the 150 air mile radius, how should any Pre-Trip or Work (All time at a plant terminal or facility), be shown in my ELD (Motive)? On-Duty? Off-Duty? or should I show an On-Duty Pre-Trip once I leave the 150 air mile radius?