the ratio Wp/Wf can be an indicator for the workability because when the ratio is 1 there is no need to compact it could be a self compacting concrete and when it decrease it could show that the workabilty is more less.
Sir, Workability determination by compaction factor test is appropriate for mixes with "very low" workability. For such mixes, it usually comes around 0.75-0.80. However since you are getting compacting factor as high as 0.95, don't get moved that you got a very nice workable mix. For such highly workable mixes, measurement by determination of flow will be appropriate.
For applicability of various methods, you can refer to Section 7 of IS 456, Code of Practice for Plain and Reinforced Concrete. I am attaching the same for your reference.