It occurs to me that these four units can form the basis of
several types of symbolic numbering systems, since their true
meaning is reliant on the less conspicuous "multiple of 5"
character. There is even the possibility that the two forms of
"notation" refer to numbers taken from two different pages of a
book, homophonic substitution incorporating more than one document
or page. The possibilities in this arena are endless.
We two are storing our pizza money in different jars, obviously,
but I do see the attraction of your approach. I'm putting my
pepperoni money in the "position sensitive homophonic
substitution" jar, but we're obviously seeing the same patterns
from different angles and calculating the same numbers. KUDO's!