How to check the text for anti-plagiarism for the site?

Question

Content

Who uses what services to check the text for anti-plagiarism? More precisely, it would be interesting to know how search engines check texts? Also interesting is the optimal size of the shingle.
Now I took the same text and checked it on the following services:
Advego Plagiatus 78%
Etxt Anti-plagiarism 87%
text.ru 100%
content-watch.ru 27%
pr-cy.ru 87%
It is clear that the spread is due to the fact that set different size shingla. But the testimony of the content of the watch confused me. 27% is too low. Followed the link from which the text was allegedly stolen. Indeed, the rewrite is visible. But will search engines take this into account?
What to focus on? Is it worth sending an article for revision just because of a single service, even if the others show that everything is ok?
Your experience is interesting. Thank you.