I’m going to quote something
DSLv5.0 stands for “Desired Sensation Level” and is a fitting formula which aims at calculating the best possible loudness balancing. Especially with high-frequency hearing losses, this leads to a significant increase of the not clearly audible frequencies. This may not be a good choice for people who have lived with a hearing loss for a while and use a hearing device for the first time, they can be overwhelmed with the sensory overload and this again may lead to discomfort. However, for patients who have been wearing a hearing device for a while and who are used to higher gain values, DSLv5 can be the best choice. Moreover, this formula also takes the measured levels of discomfort into account and the MPO of the hearing device is adjusted accordingly.