Organ Prelude and Fugue in A minor (BWV 543)

I saw the estimate that Bach wrote his organ prelude and fugue in A minor (BWV 543) some time around 1708–1717 based on where Bach was court organist at. Based on my own observations I think it can be narrowed down to after 1714. My argument is that in the prelude section there is what I believe to be an influence from Frescobaldi's Fiori Musicali. In bar 11 of the prelude, when the third voice enters, Bach seems to be quoting of an excerpt from a Kyrie from a Gregorian chant mass near the beginning. This could have been a direct result of his experience with Fiori Musicali, which he hand-copied in 1714. The Fiori Musicali is a collection of 3 Latin Masses, with each mass based off of a different excerpt from Gregorian chants for corresponding parts of the Ordinary. The first mass of the collection, Missa della Dominica, is based off of the mass Orbis Factor, which seems to be also quoted by Bach in this prelude.

Kyrie from Missa Orbis Factor
Red notes highlight excerpt

The excerpt in Bach's prelude

One excerpt (of many) used in Fiori Musicali

One argument for the direct influence is the that the implementation is very similar between Frescobaldi and Bach in that they both only implement counterpoint to the cantus firmus in oblique motion.

Another key thing to note is that Bach would have otherwise not have even known about the Latin Mass (being a Lutheran) or any of its practices or chants until his Leipzig years (starting in 1723), due to the fact that Latin liturgy was predominately forbidden from use during the Protestant Reformation.