Priority of overdumps vs. no tags

[thomasd3]

I am wondering why the overdumps [o] have priority over titles with no flags?

for example:

Galaxian.zip :OK:4:Galaxian (1982)(Atari)[o].zip :KO:-4:Galaxian (1982)(Atari).zip :KO:-6:Galaxian (1982)(Atari)[o2].zip :KO:-105:Galaxian (1982)(Atari)[b].zip

In this case, the one with -4 (no flags) should be preferable to the one with +4 (overdump). Or is there a reason to value the overdumps?