If your lenses are either telephotos or retro-focus designs, the "marking point" would be outside the body of the lens.
You need to use the other tools available for this purpose unless and until you determine where the nodal point is.
Wait I'm confused what other tools? The only tools available to me are my reciprocity timer, which asks me about the Bellas distance, however if the bells distance includes this extra space that is outside of the lens area, how can I tell where on the lens this point is? I don't see any special marking telling me where that point is like you do on a 35mm camera which has that zero with a line through it showing that that is where the film plane is, so how can I know?
~Stone | "...of course, that's just my opinion. I could be wrong."~Dennis Miller