I have sitting in front of me a set of prints taken at 50 ISO and 100 ISO and can not produce the amount of noise that you have on your prints. Either your camera is producing more noise than mine or your pictures are a section from a print far greater than 10 x 8. I think it may be the first. No two cameras are going to be exactly the same. Maybe I am lucky and I have one of the batch that produces less noise.
Iím in England but I converse with a fellow FZ1 owner in the States and he was the one that put me on the test between 50 and 100 to see if on an average picture I could see the difference. And we both agree that the very very slight difference was not worth worrying about. Neither of us produces the amount of noise your camera does at 100 ISO.
I wonder what other FZ1 owners have found.