This difference in the variation can be observed in the average edit distance between the prompts of each class, which is 3.27 and 2.73 for mined and paraphrased prompts respectively.
the improvement led by ensembling paraphrases is still significant over just using one prompt (Top1 vs. Opti.), raising microaveraged accuracy from 32.7% to 36.2% on BERT-base, and from 37.8% to 40.1% on BERTlarge. 