Input files

I have a Canon 7D and typically use its RAW files as input to SNS-HDR, but I have seen some hdr software that recommend using jpgs or TIFFs as input. One went as far as to say that using jpgs as input creates a better output image (although I cannot imagine why). some questions:
1) Is there any reason for using something other than the RAW files as input? and
2) If so, what file format would be best to use as input to SNS-HDR?
My experiments have shown that if I use Dxo (my PP software) and create TIFF files and then use those as input to SNS, the results do not appear to be as good, but perhaps I should be using some other conversion software prior to SNS? Or perhaps it makes no difference? Or perhaps RAW makes the best input?
Thanks.
1) Is there any reason for using something other than the RAW files as input? and
2) If so, what file format would be best to use as input to SNS-HDR?
My experiments have shown that if I use Dxo (my PP software) and create TIFF files and then use those as input to SNS, the results do not appear to be as good, but perhaps I should be using some other conversion software prior to SNS? Or perhaps it makes no difference? Or perhaps RAW makes the best input?
Thanks.