Ubi Caritas style

I've listened to a couple different Ubi Caritas settings and can't seem to get the repetition they are doing. Can explain what is the (usual) thing to do?

Here's a thingy.  (Below)  There's the original chant that is a prescribed part of a church service, and always done the same way, like the Lord's Prayer is always said the same way, and like everyone in an Episcopal church knows when to stand up and when to sit down and when to kneel.  Some church denominations still have much of the service sung by the priest and cantors.  (Armenian church).  Anyway, here's a thingy about it:

https://forum.musicasacra.com/forum/discussion/6665/five-5-different-versions-of-the-ubi-caritas-chant-for-holy-thursday/p1 

There are also choral anthems that are based on the original chant, but act as stand alone musical moments in a service to be sung by the choir or can be sung by secular choirs in regular old concerts.  They can change the original setting of the chant however the composer chooses.  

The Durufle is a famous one:  https://youtu.be/l1BTWCpEFRQ

Ola Gjeilo has recently put out this one, which is gaining popularity rapidly:  https://youtu.be/Xp3IHBSyZKY

You can hear the original chant in both of them, but both composers add elements of their own as well.  

Hope that's a help.  I don't know much about chant.  I grew up Episcopalian, so there was a little of it, but not as much as there is in other religious denominations.  

Here's one of the traditional chant with the text rolling along so you can follow it:  https://youtu.be/b_QEP-RHYLY

Note, they sing "Ubi caritas est vera, Deus ibi est" instead of "Ubi caritas et amor."  (Where charity is true, God is there, not Where charity and love are, God is there).