Yeah, personally I would probably defer to keeping the inflation within the specifications of the tire manufacturers even if the deflection guides suggest lower PSIs are 'optimal' -- simply because there's no way a pinch-flatted tire resulting from underinflation would exhibit better performance than using a 'sub-optimal' pressure that increases likelihood of preventing a pinch flat. Eg. Michelin doesn't recommend below 87psi or over 116psi on its road tires, no matter the weight.. Of course there's likely some margin of safety on both ends of the scale, but I wouldn't probably extend more than another 10psi either way. Tire Pressures - How to fit (Video) | Welcome to MICHELIN Bicycle - North America

(BTW, the below link has a couple options that do similar calculations) to your linked article
Bicycle tire pressure calculator