Thanks! Yes, it really was Power On. The code came from a built-in on the pronto TSU 3000 (Device: DVD(R) Manufacturer: Panasonic; code: 704; Function: Power On). I taught the code to another remote, then read it back in via my pronto, so it could have gotten a bit garbled in the translation
The codes for power on and power off you sent worked perfectly. Interestingly, the code for power toggle had no obvious effect. Here's the code I learned from the original Panasonic remote for power toggle: