With the first part you mentioned you are right cause it was 4096 when i was using the 12 bit dac and i changed the number only.
and i just noticed that in the end of the code i had before the function dac.setvoltage(value, False).
and i have to replace that one now for the 16 bit and i dont really know how cause that function was linked with a library. and the max5217 has no library. Do you have any idea for this?