You see I am using an older version of ACAD than you.
Even the var name has changed.
That happened somewhere between R14 and 2k2
DIMASO became obsolete
DIMASSOC=0 - Dumb entity dims, text, lines, solids
DIMASSOC=1 - Associative Dims like we're used to
DIMASSOC=2 - TRANS-SPATIAL Dims; dims in PS read the actual MS length (not real stable in R2K2, sometimes a 12'-0" model dim shows up as 3")