1)  The Ambrosian Rite is as old as, if not older than, the Roman Rite.  Throughout its history, there have been "Roman" adjustments and adoptions.  For example, in the above schema, the psalm cursus for Vespers is of Roman origin.  Matins and Lauds, initially one unit, were separated into two hours after the Council of Trent.

        2)  In the above table, there are, for those used to the Roman Rite or one of its variants (Carmelite, Dominican, Carthusian, etc.), elements not found in various usages.  Among them:

• Decuria - There are 10 decuriae which run from Monday through Friday for two weeks; Saturday and Sunday are not included and have their own cursus.  A decuria has 3   nocturns, but there is no rule as to the number of psalms in each Nocturn.  The Gloria Patri is sung/said at the end of a nocturn, not after each.  

• The Monday of each week generally indicates which week of decuriae will be used;  for example, on the Monday after the 5th Sunday of Pentecost, the notation for the decuriae is "Beatus Vir" (Ps 1), which begins decuria 1,( i.e. week one).  The Sixth week after Pentecost will, of course, use the second week of decuria

• There are no antiphons for the psalms of Prime, Terce, Sext, None or Compline.  There are antiphons for Matins and the psalms of the decuriae (though each nocturn has but one antiphon), as well as for Canticles and Vespers.
• In most of the hours, the hymn begins the hour (Matins, Prime, Terce, Sext, None, Compline).
• There is no invitatory at Matins, but there is a responsory after the Hymn, which in ordinary time, is taken from Psalm 94 (the usual invitatory psalm in the Roman Rite).
•  The use of the Direct psalm (which is sung/said by everyone together) and the addition of the psalms of 4 verses (see Lauds and Vespers, above) is a feature of the Ambrosian Rite.
•  Structurally, the hours are somewhat different from the same hours in the Roman Rite, as are the texts of the prayers, hymns, etc.
• The Latin Psalter of the Ambrosian breviary (and throughout the other liturgical texts in the Ambrosian Rite) does not use the usual Vulgate translation, but is the first of St. Jerome's Latin translations of the Bible, made about AD 383;  it is also used at St. Peter's in Rome.  The translation was a revision of the Vetus Itala, the oldest Latin version of the Bible. The Vulgate version which became official was his second revision, popularly called the "Gallican" Psalter.
• The Office also makes use of the Completorium (not to be confused with Completorium Quotidianum, which is Compline).  which is a short verse; there are also Psallendae, which are also single verses.
• Responsoria are constructed like those in the Roman Rite, but are used at several places: a)  post hymnum (after the hymn at Matins and after the hymn at Vespers on solemn feasts), b) inter lectiones (after the readings of the Office),  c) cum Infantibus, (after the hymn of  first Vespers of Solemn feasts), d) in Choro (after the hymn at Vespers on Sundays, the 2nd Vespers of Solemn feasts, and sometimes after1st Vespers of feasts), e) in Baptisterio (at Lauds and Vespers of some feasts, on ordinary days, after the 12 Kyries at Vespers; f) Diaconalia or Quadragesimalia (for some days in Lent), g) lucernaria (which begin Vespers), g) ad cornu altaris (at Lauds before the Direct Psalm on some days, like Christmas, Epiphany, etc), h) gradualia (after the hymn on ordinary days in Lent).
• A triple Kyrie Eleison is used throughout the office (e.g., after the antiphon for a psalm  is repeated at the end of the psalm);  12 Kyries are found at Lauds.
• Alleluia is Hallelujah in the Ambrosian Rite.
• It is important to remember that the Calendar of the Ambrosian Rite is very different from that of the Roman Rite.  There are, for example, 6 Sundays in Advent, the first coming on the Sunday after St. Martin's day, which is November 11th.  Lent is begun on the 1st Sunday of Lent;  there is no Ash Wednesday.  In order to avoid interruption of the Lenten season, some feasts which fall during the Lenten period are celebrated during Advent, e.g., Annunciation, normally on March 25th, St. Joseph, normally on March 19th.
• The pre-Vatican II breviary is a 4 volume set (Winter I, Winter II, Summer I, Summer II).  There is currently a revised Ambrosian breviary of 5 volumes (a reprint has been done), as well as a people's office book called Diurna Laus, which has some popularity.  Both are in Italian.  The new Roman Liturgia Horarum has had a major influence in the current Ambrosian breviary.
• Among the other peculiarities of the (above schema's) office, it should be noted that at Lauds, the Laudate psalms (148, 149, 150, 116) are treated as one, i.e., they are under one antiphon, and concluded by only one Gloria Patri after Ps 116.
• At the Magnificat canticle in Vespers, after the Gloria Patri, there is always a repetition of the versicle: Magnificat anima mea Dominum, which is followed by the repeated Magnificat antiphon and the 3 Kyrie's.
• Although this psalter schema is configured to conform to other Psalter schemas in these pages, it should be remembered that the liturgical day in the Ambrosian Rite begins with 1st Vespers.