I'm BP I and never been hospitalized, though came close. I would consider all symptoms over just one.
Oh, hospitalization or incapacity does not change anything if it is for depression.
One criteria to distinguish between BPI and BPII can be mania that incapacitates you OR requires hospitalization. There is no number of days involved in the DSM for bipolar.
could be that you had psychosis so they decided to put you in hospital. BP II can be associated with psychosis too.
I was originally diagnosed with BP II, which is more on the depressive end of the spectrum with hypomania. As soon as I had a full-blown manic episode with psychosis that lasted, my diagnosis was changed to BP I. I don't see why/how a hospital stay length would affect that. Definitely talk to your psychiatrist about it, but I highly doubt your 16-day hospital stay would change your diagnosis unless you exhibited things during that stay that your psychiatrist was not aware of since you didn't tell him/he doesn't live with you and didn't realize the severity of.
Generally for any diagnosis it usually lists several criteria and which number of them have to be met to meet the listing for it but you could ask your psychiatrist more about that. I don't believe the amout of days spent in a hospital alone would change a diagnosis. It just might mean this time they believed more follow up was needed and they had more concerns this one time but you could ask them that as well.