Can a Bank elect to be examined as an ISB for one examination and then change that election to be examined as a large bank in a subsequent examination?

I used to work for an ISB. I would report my data every year so I could maintain the option on being an ISB or a Large Bank. The examiner would always ask me at the beginning of each exam which way I wanted to go. The key is you must report your data to the FFIEC to maintain this option.

As long as you are not a large bank (and therefore must be examined as a large bank) and you have voluntarily filed your CRA data you have an elective to be examined under the Large bank standards if you want. There is nothing in the regulation that says once you elect to be examined as a large bank you must always be examined under those standards.

I use to work for a large bank that later became an ISB and we were given the option which way to go.

That makes sense if you had been reporting your CRA data. Effectively you became an ISB and would be evaluated that way, but you would have the elective to choose Large Bank if you had reported your CRA activity.