It is a great relief and exciting to see our Visa bulletin move dates by months from days. Trust me, it is exhilarating to see the notification on my Mobile in the 2nd week of every month. But Visa bulletin is just one of many aspect of getting a green card.
Biometrics - Regardless of 2 weeks or 4 months movement all the I-485 applicant have to go through the Biometrics appointment to give the Finger printing to their local ASC (Application Support Center).
Missed your Biometrics Appointment? Dont Worry follow the instructions here.
Already gave Fingerprinting in less than 15 months, there is a chance your finger printing might be reused
FBI Background Checks - Any government division have limited resources to handle the backlog of background checks especially on Immigration checks. The more the applicants more the wait time to get this cleared. Check for more information here
USCIS Processing Times - DHS and USCIS are two different government organizations. DHS manages the visa numbers but USCIS processes them, if they don't process in time before the Fiscal year all the visa numbers are wasted. In normal situation this should not be a problem, but with COVID-19 impacted their workforce this can slow the entire process down.
These are some of the high-level items and there are other moving parts as well like Card Printing backlog, Consular Processing e.t.c
Hoping these other dependent organizations come back to their fullest capacity before October to make use of all the available spillover visas that has been released in the Visa Bulletin.