You aren't reading that report correctly (or you aren't convincing anyone you found an answer).
Both, in fact!
That document gives the reliability figures for the solder joints on Altera
packages. The column with the heading "die size" is probably the maximum die size or else the size of the die that was in the package when they tested the package's reliability. Either way there are two rows for "F780" with wildly different numbers in the "die size" column, so interpreting the column to mean "every chip in this package has this die size" is obviously incorrect.
