^^This, always make sure you wait at least an hour (a good hour) before re-dosing.
I also agree that you would take more xanax before taking more hydro (if the need arises). Another option would be to add an antihistamine (such as benadryl/diphenhydramine) to the mix to counter-act the itching and nausea that's going to probably come with that dose of hydrocodone.
On a side note, I'm with you, purple_cloud, I've had all kinds of brands of hydrocodone (even the legit Norco (R) ones), and I haven't found much of a difference, if any, from the brand name to the generic.