My focus was on making the multi-element case to produce a more consistent result as the single element case

That would be great since the OP asked for the single element case to stop "behaving differently". Unfortuantly, KeyAttr=>[] doesn't achieve that goal at all.

Default

Multiple: $tree->{type}{default}{report}
Single:   $tree->{type}         {report}    Inconsistent


KeyAttr=>[]

Multiple: $tree->{type}[0]{report}
Single:   $tree->{type}   {report}          Inconsistent


ForceArray=>[qw( type )]

Multiple: $tree->{type}{default}{report}
Single:   $tree->{type}{default}{report}    Consistent


ForceArray=>[qw( type )], KeyAttr=>[]

Multiple: $tree->{type}[0]{report}
Single:   $tree->{type}[0]{report}          Consistent
[download]