Hi baddog,
If the ILD is correct then of course 44 ILD would be firmer than 40 or 36 ILD but I would keep in mind that ILD numbers are never exact with latex and in some cases ILD testing can vary depending on how the ILD is tested and the thickness of the core that is being tested. Dunlop latex cores are generally poured to density ranges rather than ILD and similar densities will have a similar firmness if the type and blend of latex is the same (see post #6 here for more about ILD ranges).
You can also see the ILD ranges relative to density for 100% natural latex made by Latex Green (which is most likely the Dunlop supplier in both cases) in post #2 here.
Phoenix