If a parameter value on the Render pane starts with a leading 0, it is interpreted as an octal number.
So, if I understand correctly, "1" will be read as decimal and "01" as octal?
The best, "most correct" format is the one with parameters, D and F. One reason is that the RC5 format toggles, so there is not one but two rendered form of a signal given by D and F. (For T=0 and T=1 respectively.)
This explains the problem I am seeing -- for many of the codes, I was seeing a different T value from Charlie. It seems that the renderer shifts from T=0 to T=1 if you click "Render" another time with the same input. Do I have this right?
How does the T value affect the behaviour of the IR code?