99 is quite loud. You'd be surprised how much more power will spill from the 7005 if you turned it up. Don't be scared - as long as the amplifier and speakers have been well matched, you'll be fine to turn it up. Most volume controls aren't linear, so 50 wouldn't be half way - more like 70, or even more.
Can you change it to run from infinite up to 0dB? If so, it'll usually run over to +15dB or something, and you'll be fine driving it at 0dB.