You should review your documentation to see if a cause was attributed to your tinnitus. Under the old rules, if the tinnitus is not attributed to the hearing loss, then the tinnitus is a separately claimable disability. In my case, I was awarded 10% for my tinnitus, and 2% for my hearing loss. The tinnitus disability is awarded at 5% for mild or moderate tinnitus, or 10% for severe. Severe tinnitus is that which requires a masker device or other modality (a hearing aid which is performing the function of a masker counts).
I just recently got a favourable decision on the final appeal to raise the tinnitus amount to 10%. It had only been approved at 5% previously as the specialists hadn't made it crystal clear for the VRAB that my hearing aid was prescribed specifically for tinnitus. Now any change to the disability will be based on any degradation in my hearing.
edit: I should add that my claim was under the Pension Act, not the New Veterans Charter. Looking at the 2006 Table of Disabilities, tinnitus is separately claimable from hearing loss, regardless of cause. If your tinnitus is constant, and requires the use of a masker (or hearing aid acting as a masker), then you should be getting 10% for the tinnitus alone.
If you want the references cited in my appeal, please PM me and I'll be happy to help out.