I have often also wondered about this. It does appear from the smoke trails of very many cars that one can drop into the 22° quicker than the template suggests. However, these cars are ultra smooth already and I can see how sticking close to the template would be a safer bet for the DIYer.
Another thing to consider is the small amount of foreshortening in all of these photographs, which might of course appear more confidently to veer away from the template, but in fact does a little less so.
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