what the heck, I'll give it one more shot. After this, if you don't understand me, then may god help you, because I can't.
El Norte has probably adapted to what is playing right now in Monterrey N.L. and the whole state of Tamaulipas (in other words, what is "hot" in Norteno stations). If duranguense is in heavy rotation in northern mexico, then it is probably no surprise that KQUE is also playing Duranguense. El norte doesn't represents itself on the songs it plays, but on the people who listen to it, which will be the "regiomontanos" and Northern Mexico natives. Just because the name is El Norte, it doesn't mean they will only play Norteno hits. (This is what a friend at a local spanish station told me. this may not necessarily be the case at LBI, but it may be very similar.)
If you're a little confused, take some time tonight and listen to Monterrey's Clear Channel XEG AM. Listen like around 3 AM (after that paid programming from the Label companies) and they will play some banda mixed with all the Norteno hits.