A method of adjusting a signal processing parameter for a first hearing aid and a second hearing aid forming parts of a binaural hearing aid system to be worn by a user is provided. The binaural hearing aid system comprises a user specific model representing a desired asymmetry between a first ear and a second ear of the user. The method includes detecting a request for processing a parameter change at the first hearing aid, adjusting the signal processing parameter in the first hearing aid, and adjusting a processing parameter for the second hearing aid based on the request for processing parameter change and the user specific model.</p
