All finished motor oils leave some amount of film but some may leave more than others or for a longer period of time. Typically esters (G5) with the polar properties will cling to metal but a balance must be struck so it doesn't interfere with certain AW additives. "Magnatec" is marketing of course and its meaning is whatever the consumer thinks it means. The product probably does have more esters but how much is unknown. I wouldn't be surprised if Magnatec and Castrol High Mileage oil were the same formula.
I've been suspecting that for awhile.. Being as I work somewhere where we manufacture automotive fluids (not oil, ironically, but other things...)
And how we have ohhhh about 10, maybe 20 now bottles and labels for essentially the same thing, just if its either pure product (less money for us) or with other "fillers" (more money for us, less expensive proprietary product and chemicals per unit, reflected in price..)
.. that it looks like "GTX with an additive" to me
And is probably still "Worse than Edge.'
And you are correct, that's how marketing works. 6 oils, from $13 to $25. Well, if you can spend $13.. why can't you spend $17?
And.. okay, $17. Well, why not $19?
And, now, just above that. . $21 now $24, oh there's Mobil 1 and Edge next to a 20,000 mile oil. Do I still want to spend just $14?
I was getting "ZMax soaks into metal!" vibes from it..
Maybe $1 more of additive over GTX. Sold for $5 more..
Meanwhile, Supertech is $14, meets API SN spec, and Mobil 1 is sitting there $24 as the best oil there is, next to two oils like it...