Lectio discontinua

Ah, back to the lectionary. You know, the thing that radical Protestants hate:

Many Zwinglian influences remain (or at least should remain) a force in our Reformed Protestant heritage, including orderly/austere worship, an intellectual approach to faith, simple music (often with no instruments and often psalmody-only), and NO LECTIONARY! Here’s why:

On January 1, 1519, Zwingli chucked the lectionary and began preaching through every verse in Matthew’s Gospel (lectio continua or continuous reading). When he finished that, he moved on to the Acts of the Apostles. When he finished that, he moved on to the Epistles. Then the Old Testament. And one by one, he preached through all the books of the Bible, which was radical at the time and remains a unique fixture of our Reformed heritage.

Anywho, for a long time I believed something like this:

The 1662 Book of Common Prayer ... gives, for the most part, the same Sunday Collects, Epistles, and Gospels as the Missal of S Pius V. But the Reading and Gospel for last Sunday, the Sunday Next Before Advent (taken, like most such Prayer Book material, from the medieval Sarum Rite) were, unlike the other Epistles and Gospels After Trinity, quite different from those in S Pius V's edition of the Roman Rite. But they are nevertheless thoroughly respectable choices in terms of Tradition; they go back to the earliest Roman lectionaries, the Comes of Wuerzburg and Murbach.

"For the most part" is better glossed as "about 65%," based upon my informal survey. (I think that a divergence of more than a third is somewhat significant, after all.)

So, I know of no way at all of determining the answer to this question:

I know that the lectionary for the Sarum rite’s mass is very similar to the readings used in the traditional Roman mass. It wouldn’t be too surprising to see the lectionaries to be off set by an equal amount (ex. one or two extra Sundays thrown in), but this is not the case. It seems, especially after trinity, that the Gospels are off set by one week and the Epistles by two weeks. Do you know of any reasons why this off-setting has occurred (whether Sarum added a reading or Rome removed readings)? Or do you know of any resources where I might study this? Thank you for your assistance.

Sigh. Back to the drawing board. The answer is not in a book.

UPDATE:

For instance, this is very interesting and probably true but still doesn't answer the question:

Many details are revealed by a study of the lectionary. The gospels for the Sundays after Pentecost in the Gregorian-Beneventan tradition match closely those of the lectionary of Würzburg, whereas almost all other medieval traditions follow the order in the lectionary of Murbach. But Würzburg, the oldest surviving Roman lectionary, represents the Roman liturgy of the mid-seventh century; its calendar is that of the early Gelasian sacramentary of the sixth-seventh century. Murbach, however, the ancestor of the universal medieval and modern tradition, has the calendar of the eighth-century Gelasian sacramentary, and represents a Frankish adaptation of the mid-eighth century uniting the Gelasian and Gregorian sacramentaries [19-20].

As I have established here, while Sarum does indeed follow Murbach, Trent does not follow Würzburg.

Who cares? Well, one ought to, if, for instance, one hopes to avoid the obvious incoherence of crudely adapting the Tridentine antiphons to a completely different system!