Yes. You might want to compare your APN settings with AT&T’s recommended APN settings (or if your carrier is an MVNO on AT&T’s network, go with the MVNO’s recommended APN settings).
You might also want to confirm that the L5 is actually saving and using the carrier’s settings. I’ve noticed in the past that it can be temperamental in this respect. (It can also depend on AT&T’s actual coverage in your area; is it normally good for 4G with other devices?)
About the wiki, I have editing rights, so I’ll add some comments to reflect the shutdown of AT&T’s 3G; those entries were written while 3G was still operational.