Facet drop odds question

Hi there, im finishing up my chronicle and im missing a facet. Im planning my runs and looking at the odds I have a doubt and maybe somebody here knows.

Are the drop odds for facets in calculators for a particular facet, or for any facet? Looking for example at latent sunders over at maxroll, they are for a specifc sunder (its easy to verify because they have different odds depending on which). However for facets since they are all the same (1/8 for each).

For example lets say duriel with 387 mf has 1:2774 for a poison die. D2-dropcalc.in says the same, but silos pen has 1:5055 but doesnt specify a type

So if anyone has an idea, id appreciate it, thanks!