SFF is an input format. So is PD. DFSORT can convert a value in any input format to many different types of output formats including lots of different output formats with decimal points and blank for a positive sign, so the answer to both your questions is yes. See the following for more information:
I think the first one (editing) is more relevant to what you want to do.
If you need more specific help with the exact editing masks to use or anything else you want to do with the data, show me an example of your input fields and what exactly you want the output to look like.