program 2003 suburban keyless entry remote

Two questions:
Can you have two #1 remotes programmed to the vehcile?

How do you program a new remote?

Yes you can program 2 #1's but the luxury functions wont work right sometimes.

Sit in truck, close all doors
Insert key in ignition but DO NOT TURN
Press unlock button on power door lock and hold until I say let go
Turn ignition ON, OFF, ON, OFF
Release power door lock switch
door locks will cycle
Press and hold LOCK & UNLOCK on forst remote fo 15 seconds
locks will cycle
Press LOCK & UNLOCK on next remote for 15 seconds
lock will cycle
Turn ignition on to exit programming mode

Up to 4 remotes can be programmed. When entering programming mode all remotes will be erased.