Interesting perspective - this Naked PE.
SML contributes to earnings so attributing a cash value to that shareholding and stripping it out and coming up with a forward PE based on a rather creative "attributed" cash value looks pretty "creative" to me. If ATM didn't have that shareholding I doubt they could lean on SML for such good supply arrangements so that shareholding is an integrated part of their business model in my view and probably confers meaningful earnings power to ATM beyond ATM's share of SML's reported earnings.
Happy to stick with my analsysis and valuation clearly articulated earlier today. I'm not getting caught up in the "hype" that this is a "major" upgrade.