What does "storage" mean (in the DDS manual)?

Maybe few people use DDS anymore, let alone the DDS manual, but I'm
wondering about the section "Length for physical and logical files
(positions 30 through 34)" in Chapter 1 of "Programming DDS for
physical and logical files" (rzakbmst.pdf).

There it states "The system determines the number of bytes actually
occupied in storage as follows:" and for date, time, and timestamp, it
gives the "buffer length" which has been established numerous times on
this list as not the length of the field on disk.

I wonder how many people look at the DDS manual and think that "bytes
actually occupied in storage" means "bytes actually occupied on disk".
I'll bet it's a very high percentage (of the 7 people who consult the
DDS manual).

I think it's worth updating the manual so that it's clear that using
the L data type is not only more convenient than (for example) 5-byte
packed (8 0), but actually even saves disk space!

John