It depends on what you are mixing here. If you are trying to mix hose and hose ends from different mfg, then you may have issues as individual hose mfg may have different O.D. and that what the hose coupling/fitting is designed for. Think old school and Granimals clothes. Keep them matched and not mixed. Also, this "AN" hose you see listed is different in I.D. from industrial hose. The AN stuff is usually spec'd to be similar to tubing I.D. and not true I.D. as the size would indicate. Look up Fragola FRA-842006 on Summit's site and look at the I.D. It's less than 0.375" (0.344") and the O.D. is 0.560". Now compare that to Earl's Vapor Guard EAR-752066ERL and you'll see the I.D. is 0.375" and the O.D. is 0.625. These are critical dims in choosing the correct hose ends if you are going with resuables (screw together) hose ends.

Now when it comes to connectors/fittings, then the as long as the flare is 37deg you can mix and match parts, brands, material all day long between JIC and AN. Those are based on the thread size of the fitting.

And just an FYI...AN/JIC sizes are based on 1/16th's. 4=.25", 6=.375", 8=.50".....etc