It may have to do with length of the manic episode or when psychosis occurs

Also, you can ask your psychiatrist. He may not know enough about your symptom duration to diagnose you

The basic difference is this: Bipolar 1 w/ psychosis means that you only experienced the psychosis while also having either a manic or depressive episode. Bipolar Schizoaffective Disorder is just a fancy way of saying you have both Bipolar and a form of Schizophrenia, meaning you can experience psychotic symptoms at any time - even if you're not having a manic or depressive episode. And to receive an official schizophrenia or schizoaffective diagnosis, you must have been experiencing at least two symptoms of psychosis (including delusions, hallucinations, etc.,) for six months or more. Not sure if you know what the Diagnostics and Statistics Manual version 5.0 (DSM-V) is, but it's basically the psychiatry bible. It lists mental illnesses and the criteria required for a diagnosis. I think most libraries have a copy.