Egypt 20 Para Mahmud II 1223 Question [solved]

I am probably being dense and missing something really obvious…. 🤔

This coin just says its composition is Billon but no split down as to exact composition.

20 Para - Mahmud II - Egypt – Numista

This coin with Billon as its composition says its exact the split down composition some others have a slightly higher listing of silver content at 0.400 but using the 0.350 as the example …. Google does say that Billon can be between 10% and 30% …. but then again if I Googled my cold symptom's it would likely say I have the bubonic plague!

5 Cents "Jefferson Wartime Nickel" (1st portrait) - United States – Numista

The second one listed has a bullion value but the first doesn't. Is there a reason for this or is it that just nobody has found out the exact composition of the first one to add the bullion value or is there a Billon that doesn't have any silver in it?

The first probably had various amounts of silver (notice the difference in weights) and exact compositions are probably not known. On the other hand the wartime nickels were well document to exact weight/composition by the US Government 

and until a some months ago was not listed as billon, but silver composition. 

From Aug. 2022

Thanks rsirian1 as usual your a very helpful mine of information 👍