Uscis receipt number format explaination

The information given here is misleading.

E.g. check WAC-22-209-50105

This number is allotted by USCIS for a case which was received by them on April 28, 2022.
209th working day falls on 5 Aug 2022 for fiscal year starting from 1st oct 2021.

Any thoughts?

USCIS year starts 1st Oct, ending 30th September. Its says right at the start of the article.

Yes, 209th date from 1st Oct 2021 excluding holidays is 5th Aug 2022.
Check the receipt number WAC-22-209-50105 at USCIS website. It was received by them on April 28. So how come 209 was assigned, that is my question?

As per the logic given in the article it should be around 140th day - so ideally the above receipt number should be something like WAC-140-XXXXX.