Lexi on more than one device

We recently had a student who tried to load on two devices and received the following error message  the code can only be used for 1 device "Dr. N's cellphone"  Unfortunately students need to select which mobile device they want to use to access Lexi.  Students with, for example, an Iphone and and Ipad will need to choose.  Each device uses up one Lexi license.  We are only providing one license per student.  This is controlled by Lexi in when the students register.