Avid Pro Tools Artist Perpetual

Just with the limitations of how many channels you allowed to use depending on package you buy. With artist, we only allowed 16 channels, which is great, but if the interface has more than 16 channels we can't use those other channels. I got the behringer interface which has ch 1 to 8 inputs 9 to 10 spdif, 11 to 18 adat. Pro tools does not allow me to use all the adats, spdif takes priority of channel 9 and 10, I do not want to use spdif , only the onboard 1 to 8 with adat 11 to 18. At the time there was no work around to utilize all adats. I. Limited to 14 channels. I would like to have access to route all hardware inputs to the available pro tools input channels.