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):
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.)
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?