The affixing of particular books of Scripture to particular weeks in the natural calendar for the final four months of the liturgical year goes well back to the early medieval period and possibly even to the time of St. Gregory the Great, in its current rendition. Sadly, in 1960, this tradition, along with so many others, was disturbed by the rationalist principle of conforming these weeks according to the modern calendrical understandings, hence discarding the Roman calendrical understanding which the Church adopted from antiquity. The CTO, naturally, will employ the Roman tradition of allotting the occurring Scripture in which the first Sunday of a given month is the one closest, in either direction, to the Kalends of the respective month.
Therefore, in any given year, inevitably the CTO will differ from our 1962 brethren by one week for one or more months, which has its most noticeable manifestation in the observance of the September Ember Days. We have been privy to many a "discussion" among our Trad brethren using different Missals about which week is Embertide! This year, it so happens that there will be no divergence of the Ember week, but next year, it will return as it always does every 3-4 years.
That said, there are some further technicalities and differences between the Tridentine and Johannine rubrics which escape the obvious when considering these weeks of occurring Scripture. Each month has five Sundays/weeks of Scripture given, but most months have only four Sundays, so there is never a year in which all 20 weeks given have a place. Therefore, different ways of treating the superfluous weeks in a given month have been developed ranging from simple omission to somewhat complicated rubrics, varying by month, in which Sundays/weeks without a place are partially observed. The CTO aims to preserve the latter system of partial inclusion.
Let's begin looking at comparing the rubrics for the month of August (the superfluous week is noted by an asterisk).
August - Sapiential Books
Week I - ProverbsWeek II - Ecclesiastes
Week III - Wisdom
Week IV - Ecclesiasticus
Week V* - Ecclesiasticus
Post-1960 Rule: The first Sunday of August is that which occurs first in the Calendar month of August - i.e. the Sunday falling between 1 and 7 August. When August has four Sundays in the Calendar month, the fifth Sunday and its week are omitted.
Pre-1961 Rule: The first Sunday of August is that which occurs closest to the Kalends of August, either before or after - i.e. the Sunday falling between 29 July and 4 August. When August has four Sundays (determined by proximity to the Kalends on either end - e.g. the month of August could have five actual Sundays in the Calendar month but only four Sundays liturgically for this purpose because the last Sunday would be considered the first Sunday of September), the fifth Sunday and its week are omitted.
Since both the fourth and fifth weeks of August consist of Scripture taken from the same book, Ecclesiasticus, there are no instances of needing to capture the initia of respective books as will be the case in other months. Thus, the fifth Sunday and its week are simply omitted in the years where it has no place, and such is the case this year. We will revisit this topic for the subsequent months in which rubrical deviations occur to capture (or not) the missing weeks.