Dunno 'bout RC6, but RC5 has been discussed many times here before; eg,
http://www.8052.com/forum/read.phtml?id=29516

Could your "toggle bit" be related to the "Check" bit described here:

"In the Philips remotes, the bit #3 is the CHECK bit, every time you press a key at the remote, even pressing repeatedly the same key, this bit flips state. This feature is interesting. Suppose you pressed number '1' at the remote (trying to select channel 15 at TV) and holding it for 2 seconds, then your other hand just blocks the InfraRed signal. The TV would receive two trains of pulses, generated by your hand breaking a long train in two. Other systems would understand transmission of two keys '1' selecting channel '11', but this do not happens in the Philips system. This bit flips state every time you press a key, so blocking the signal with your hand doesn't change this bit, so the TV will understand that still the same key pressed. To select channel '11' you should press key '1' really twice."

http://www.ustr.net/infrared/infrared1.shtml