How to pray like a Simple Friar (Rule of Saint Francis)

How do you pray the Divine Office if you’re a thirteenth century illiterate lay brother who cannot read the Latin Psalter?
Saint Francis of Assisi set forth the following custom in his rule of 1223:

Clerics are to perform the divine office according to the rite of the Roman Church, except for the Psalter, and they can have breviaries for that purpose. 

Laymen are to say twenty-four “Our Fathers” at matins; five at lauds; seven each at prime, terce, sext and none; twelve at vespers; and seven at compline. They should also pray for the dead.

Here’s the saint’s breakdown in a simplified format:
24 for Matins 
5 for Lauds
7 for Prime
7 for Terce
7 for Sext
7 for None
12 for Vespers
7 for Compline
It all makes sense to me except for Lauds. Why only 5 Our Fathers for Lauds? Lauds has more Psalms that Prime, etc. so why so short?

ad Jesum per Mariam,

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