@sag, the audiologist limits the maximum output of the hearing aids. Even though your volume control is at maximum, it may not necessarily mean the maximum output of the hearing device. The audiologist set the max to prevent feedback, not necessarily the max of the device. You may be able to get a few extra decibels output (without feedback) if you have custom molds. Limiting the max output is the factor that separates a hearing aid from a Personal Sound Amplification Device (PSAP). Too much volume will damage your hearing so the audi will not allow the volume to exceed that level which causes discomfort. Most PSAP's amplify all frequencies the same, unlike a hearing aid, which amplifies based on your audiogram. If you've ever tried a PSAP, such as a Williams Sound Pocketalker, you may be able to hear better, but you risk damaging your hearing. I do not discourage the use of a PSAP, only point out the difference.
Tony in Michigan