I thought I would post my results in case someone else ever encounters this same issue. Just to give background...
I had an earlier version of a schmartz controller. I had a URC remote (MX-800) that started having problems with buttons, so I needed to replace it. It did have all the PS3 stuff programmed. I replaced with identical remote that was their new model, URC MX-850. I put all the old programming of the MX-800 into my MX-850. I then decided to upgrade my schmartz device to the PS3IR-1000. When I received it, I wanted to make sure I had all the capabilities available for a remote for the PS3, so I followed the directions for the URC remote. However, I could not find the code 648 for the PS3 as stated by schmatrz (and as you can see in one of the above posts, they did verify with URC that it was still the code). I wrote URC, but never heard back from them. My URC MX-850 programming software does say it is updated to the most current version, yet there is still no 648 code available. So, I just kept the old programming, but found the "off" no longer worked after I got the PS3IR-1000.
In the meantime, the 'On' stopped working. Hmmmm...what to do. I did try to 'teach' my remote with the PS3IR-1000 virtual remote, but that did not work.
Today I sat down to see if I could do the teaching again since URC was not responding to my email. This time, I plugged the PS3IR-1000 into my computer and on the utility software for it, I changed the Power Sensing to "Enabled" since I was going to have the device plugged into my PS3 appropriately. I then proceeded to teach both the ON and OFF button on my URC MX-850 with the virtual remote of the PS3IR-1000. This time they took!! I then downloaded the newly learned buttons to my URC remote and crossed my fingers that it would actually work. I reattached the PS3IR-1000 to the USB plug and the USB sensing cable that goes to my PS3. Low and behold, when I pressed the ON button for the PS3 on my URC remote, it came on!!! I then pressed the OFF button for the PS3 on my URC remote, and it worked, too!!!
I don't know if changing the power sensing to 'enabled' made the difference or what, but that seemed to be the case for my situation.
I'm still baffled as to why I cannot find the 648 code in the URC software. There is a PS3 option, but the code is 554 and does not have a lot of the functions in the menus for the PS3 (like 'eject' or the color buttons). I'll still poke around to see if I can find it, but it just doesn't seem to be there for me. So odd!! For now, the major issue of 'on' and 'off' are now fixed through teaching my remote.