Hi BostonMatt,
I’d be (almost) willing to bet the 16-18 ild Dunlop is made by Latex Green, and is 75D (density of 75 kg / m3). Clawdia and I were just talking about something similar. If you google 16-18 ild Dunlop density, you’ll get a several hits which all say 4.75 pcf (which is about 75 kg/m3). As Phoenix’s post says, I’d guess several companies have taken the Kgf from latex greens website and called it ild. 75D Dunlop would not be the softest.
My search for info brought me back to here also, with Phoenix writing about alleged 16-18 Dunlop of 75 kg/m3 density
https://forum.mattressunderground.com/t/need-feedback-on-mattress-layering-system
If you wanted to verify for your own (or with some help): Weigh the mattress pad (in kg or lbs), indicate the measurements (height, width, length), and then density can be calculated. Post the info here if you’d like… I’m happy (and frankly curious) to calculate it.
I’d guess all 4.75 pcf / 75 kg/m3 Dunlop labeled at 16-18 ild is part of the same root mislabeling / mistake.