what is the programs mean?

[deafJar]

so what does the programs on hearing aids mean i have a hearing aid that goes up to 4 programs. what does that mean? i never could figure that out and i have no clue about percentage and i asked my hearing provider how much hearing loss and i asked in db and she said that they don't know that and they don't do that way. it is confusing. i have a hearing aid that is unison essential that is what it says on the back of my hearing aid and it is a unison hearing aid ,unitron. it is blue and see through and mold is swirled in blue,green,orange.
so does the programs tell how much loss you have or what?