edgemark
You pretty well summed it up, at least what my musings were. Mac, true, and mostlikely never unsafe, but their current data, like you said, might be tested on new style brass, new powder, or new measuring equip.
At the same time, a fellow loading from an old manual, old brass and powder from a lot he's had for years, using a load he's used for years, does not necessarily become unsafe, just because he "new" manual says so. But, as you say a call is a good idea, if all of the above isn't true.
Just like my loads of BL(C)2 in my 338-06. Charges are well below the stated levels, BUT velocities are well above. Something doesn't add up and requires closer examination, hey, maybe even a call to Hodgdons, what a great idea I just had
.