12 year AF vet here with time in OIF. Just wondering, if I'm already rated at 80%, how much more will I need to get to 100% or totally disabled? I know the formula is complicated, but I'm hoping someone has experience enough to rattle off an answer. My understanding is that any additional rating will be a percentage of the 20% I have remaining--which means I need more than 50% to get me over 90% which means 100%. Is that right?