Looks like this bcame routine for all INS offices. I am in the same situation from Boston INS office.
What is an Immigrant Visa Number?
An immigrant is someone who is not a U.S. citizen but has been authorized to permanently live and work in the United States. If you want to become an immigrant, you must go through a three-step process. First, the BCIS must approve an immigrant petition for you, which is usually filed by an employer or a relative for you. Second, a visa number, through the State Department must be immediately available to you, even if you are already in the United States. If you receive an immigrant visa number, it means that an immigrant visa has been assigned to you. Third, if you are already in the United States, you may apply to adjust to permanent resident status after a visa number becomes available for you. (If you are outside the United States when an immigrant visa number becomes available for you, you must then go to your local U.S. consulate to complete your processing.)
U.S. law limits the number of immigrant visa numbers that are available every year. This means that even if the BCIS approves an immigrant visa petition for you, you may not get an immigrant visa number immediately. In some cases, several years could pass between the time BCIS approves your immigrant visa petition and the State Department gives you an immigrant visa number. In addition, U.S. law also limits the number of immigrant visas available by country. This means you may have to wait longer if you come from a country with a high demand for U.S. immigrant visas.