That’s really weird. I have tested WordAI and Spin Rewriter with Copyscape and the results were always 80%+ uniquness, even 90%+. I don’t know how u spun the content to achieve such low results, but this is definitely way too bad. As for the block spinning, I have to be honest, this is the first time I’m hearing of it and I will have to check it out when I have a bit of time, but generally, yes, in the best case scenario, you would manually touch your Tier 1 content to make it 100% human readable and as unique as possible. For lower tiers, you can do pretty much anything, but again, the better quality of content, the better results you will have. That’s in my opinion and experience.
By now, most people in the SEO industry are more than familiar with the various animal named updates that have made it nearly impossible to rank without high-quality content. One of the most famous ones is Google Panda, which directly targets on-site content quality and severely penalizes sites that have spelling and stylistic errors or were not edited well.
The instant article spinner or paraphrasing tool carefully scans the article you enter, looking for all the words that it can replace with synonyms. All the words or phrases that will be replaced are colorfully highlighted to make them prominent and easy to identify. By clicking on each of the highlighted text, you can see the original word along with other suggestions, and you also have an option to add your own word. To restore the original text, just click the original word.