Onkyo TX-SR506 Wierd Setup, Plz Help

[B0rnGamer]

Hey guys, I bought this Reciever about two weeks ago and after reading some stuff on PCM and Bitstream I figured that the best way to get good sound is to go with the HDMI cable and not the Optical wire which I am currently using. My problem is that I am already running an HDMI cable from my PS3 to my HDTV and the Optical cable from the PS3 to the reciever. and the manual says that to use HDMI cable, I have to connect one HDMI from PS3 to receiver and then another HDMI cable from reciever to the HDTV AND another Optical cable from PS3 to the Reciever. and that last step is required only for 506 reciever. now what I wanna know is that will running the HDMI cables that way, along with the Optical cable make a difference? If not then I'd rather not waste money on another HDMI cable, and just keep my current setup. however if hooking up another HDMI cable along with the Optical will get me better sound and i'll happly buy another HDMI. Thanks for you help...