The more APEGA gets involved to clarify stuff, the more confusing the issues get.
I'm not a fan...and I'm a Permit Holder, have been for 20 years.
The way it used to work - and the way it made sense to me - was:
If you do something as an engineer that someone else pays for, receives and uses towards making a decision regarding the implementation of something, you ought to be prepared to stamp it. If you're not, then you ought not to be doing it in the first place. That's why I have so much heartburn with "technologists" and "technicians" doing stuff that, simply put, they lack the credentials to do. Elitist, perhaps, but it pains me to see folks who derive a sense of entitlement to "do stuff" but are conveniently able to duck the accountability that goes with it.
To me, my stamp is my statement that says, "Here, I think this piece of work is correct, and I'm proud of it because I think I've done a good piece of work, which, by the way, I am actually qualified to do.". So, if someone wants me to do a data sheet and stamp it, then I do it and stamp it. The acid test, in my mind, is:
"OK, I've put something on a piece of paper that someone who pays me is going to use to make a decision. Would they be able to make that decision without what's on this piece of paper that I've been paid to give them?" If no, then it's stamp-worthy. If yes, then they didn't need me in the first place and they can go do their own thing, whatever that is.
I think data sheets and calculations always fall into a gray area, it's a bit overkill. That said, I have learned to simplify my life by being prepared to stamp whatever I am being asked to do, which, by extension, means that I don't do stuff that I'm not prepared to stamp. One perspective directly supports the other.
The minute, for example, someone says, "I'll do it but I won't stamp it" is the minute, in my mind, that they cease being an engineer.