Some DAWs, including Apple Logic, can deal with floating point sample values greater than 0 dBFS. If the 'Clip at 0dBFS' option is turned off, then the Liquid Mix can deal with these floating point sample values. At some time in the future, this feature will ensure compatibility with DAWs that are capable of dealing with sample values which refer to levels greater than 0 dBFS. For now, it's best to turn clip at 0 dBFS to 'ON' (e.g. ProTools use where fixed point DSP is used).