If you look on page 117 in the 2nd edition of The Daily 5 book, it say that there are two important things to remember about Listen to Reading (L to R):

1. Not everyone does L to R, or needs to. (This is pertaining to the fact that proficient readers, especially in the middle grades, really don’t need to hear the modeling of L to Reading.)
2. Opportunities and options are limited by the kinds of devices we have and the number available. (Referring to the fact that every classroom is different–if you are fortunate enough for everyone to have a device, they CAN all to L to R at the same time. However, if the number of devices you have available is limited, you’ll have to plan for that.)

The legend by Figure 7.5 states that *“The number of computers in the classroom determines the number of students who can do L to R at one time.”
It really never say that the whole class can not practice L to R at the same time.
Does that clarify what you are asking about?