wrong indentation

[VladimirAlexiev]

Consider this fragment (incomplete):

Vocabulary =
  element Vocabulary {
    element Subject {(
      element Ancestors {(
        element Preferred_Ancestor_Branch {
          element Ancestor {
            element Immediate {ParentType},
            element Other {ParentType}*}}
      & element Non-Preferred_Ancestor_Branches {
        element Non-Preferred_Ancestor_Branch {
          element Ancestor {
            element Immediate {ParentType},
            element Other {ParentType}*}}+}?),
        [ a:defaultValue = "300000000" ]
        attribute Broad_Parent_ID {VP_Subject_ID}?}
    & element Associative_Relationships {
      element Associative_Relationship {
        element Description {xsd:string}?
      & element AR_Date {
        element Display_Date {xsd:string}
      & element Start_Date {Geog_Date}
      & element End_Date {Geog_Date}}?
      & element Historic_Flag {associative_rels_historic_flag}?
      & element Relationship_Type {ar_code}
      & element Related_Subject_ID {
        element VP_Subject_ID {VP_Subject_ID}
      | element Contrib_Subject_ID {xsd:string}}}*}?
    & element Descriptive_Notes {
      element Descriptive_Note {
        element Note_Text {xsd:string}
      & element Note_Language {language_code}
      & element Note_Sources {
        element Note_Source {
          element Source {SourceType}
        & element Page {xsd:string}?}+}}*}?

I think the indentation is wrong. It puts these two at the same level, but the second is nested:

      & element AR_Date {
      & element Start_Date {Geog_Date}

I'd prefer if the words "element/attribute" are aligned properly, and the punctuation &|(< is ignored (visually it doesn't have a lot of weight. But even if that's not possible and it aligns the punctuation, it should indent consistently,

[VladimirAlexiev]

I can send a file (Getty_Vocabulary_CONA-nocomment.rnc) that's the result of trang and is better formatted.
Then play with it using this mode's indentation, and you'll see how it breaks it.