Luther Celebrated The Feast of the Assumption?

I followed a rabbit trail from a CARM discussion about Martin Luther observing the Marian feast day of the Assumption. My journey begins here:

The Lutheran pastor and scholar, Charles Dickson, notes that “the feast [of the Assumption] celebrated by the Church on August 15, dates from the forth century, when numerous festivals honoring our Lady were common practice.” The history of Church feasts demonstrates that these celebrations grew from beliefs that existed long before the feasts themselves were formally inaugurated. “Interestingly enough, the sixteenth-century Protestant reformer, Martin Luther, included this feast on a list of liturgical celebrations that should, in his words, ‘be observed among Evangelical Catholics as a sign of continuity and order’ Charles Dickson, A Protestant Pastor Looks at Mary (Huntington, Indiana: Our Sunday Visitor Publishing Division, Our Sunday Visitor, Inc., c. 1996), pp. 83-84.[source]

I don't have A Protestant Pastor Looks at Mary, nor do I plan on purchasing it. That doesn't mean the trail ends. Here's my next stop: New Book of Festivals and Commemorations: A Proposed Common Calendar of Saints By Philip H. Pfatteicher. On page 397 comes the following:

Here's "Concerning the order of public worship" (1523). Anyone familiar with this time period knows that the church of Wittenberg was going through a structural crisis. Karlstadt had been far more radical in seeking to immediately overhaul the church. Luther though wanted subtle change to occur. Luther wrote this treatise as guide to church order, both daily and annually. He states:

All the festivals of saints are to be discontinued. Where there is a good Christian legend, it may be inserted as an example after the Gospel on Sunday. The festivals of the Purification and Annunciation of Mary may be continued, and for the time being also her Assumption and Nativity, although the songs in them are not pure. The festival of John the Baptist is also pure. Not one of the legends of the apostles is pure, except St. Paul’s. They may either be transferred to the [closest] Sunday or be celebrated separately, if one so desires.[LW 53:13]

According to Eric Gritsch, Luther then went on to abandon the festival of Mary’s Immaculate Conception and her Assumption:

“He rejected the festivals of Mary's Immaculate Conception, December 8, and her Assumption, August 15.” [Lutherans and Catholics in Dialogue VII, 240].

“According to Luther Mary should be honored in festivals that focus on Christ, which is why he eventually rejected the celebrations of her Immaculate Conception (December 8), her birth (September 8), and her Assumption (August 15). He did honor her in the festivals of the Annunciation (March 25), the Visitation (July 2), and Purification (February 2), since these are connected with the birth of Christ. "We dare not put our faith in the mother but only in the fact that the child was born."[Ibid. 241]

“Luther continued to preach on these festivals, but stopped preaching on the other three festivals after 1523.”[Ibid. 382]