Consulate selection in DS160 and on ustraveldocs.com

[bhavinbm]

As far as I understand, for scheduling an appointment for visa stamping (H1-B), we have to now go to ustraveldocs.com
Before I do this, I need to file DS 160. Here on DS 160, I need to select consulate.
What would happen if say I select Mumbai as consulate on DS160 but then I am unable to make an appointment at Mumbai and have to book in Delhi instead?

I remember that last year, Mumbai consulate was not even processing H1-B. How do I know if appointment for H1-B is available at all in Mumbai consulate before filing DS 160?

[immihelp]

That is a catch-22 situation, unfortunately.

[bhavinbm]

Got this from the state.gov website

"The Embassy or Consulate at which you actually apply should be able to access your form using the barcode on your DS-160 confirmation page, which you must bring to the visa interview. For example, a business traveler intends to apply for his visa at the U.S. Embassy in City X, so he selects City X as the location where he will submit his application when he completes his DS-160. He then has an urgent reason to travel to City Y on business. Because there is a U.S. Consulate in City Y, he schedules an appointment for a visa interview there, using the barcode from his completed DS-160 application for appointment scheduling. The U.S. Consulate in City Y is able to accept his DS-160 even though it lists the U.S. Embassy in City X as the location where he originally intended to submit his application."