Rating Coexisting Respiratory Conditions Any Ideas?

[Teac 3]

I was diagnosed with sleep apnea... I am already 100% due to asthma and COPD. My doctor indicated in writing that it is more likely than not that the Sleep apnea is secondary to my asthma/Copd because I have Chronic respiratory failure with carbon dioxide retention and need to use a CPAC machine. This is ratable at 100%.

Now If I understand the rating schedule, I cannot be awarded one rating for sleep apnea and another seperate rating for Asthma/Copd. In other words I only get one rating for all three medical problems. Am I correct. Also if I am correct will the va consider any extra schedular rating due to the severity of my lung problems?

4.96 Special provisions regarding evaluation of respiratory conditions:

Rating coexisting respiratory conditions. Ratings under diagnostic codes 6600 through 6817 and 6822 through 6847 will not be combined with each other. Where there is lung or pleural involvement, ratings under diagnostic codes 6819 and 6820 will not be combined with each other or with diagnostic codes 6600 through 6817 or 6822 through 6847. A single rating will be assigned under the diagnostic code which reflects the predominant disability with elevation to the next higher evaluation where the severity of the overall disability warrants such elevation

My asthma and COPD fall under 6602 and 6604 and are rated as one.... but apena will be rated under 6847.... so could this mean that I can get two seperate ratings? Or does it mean like I suspect that any respiratory conditions within 6604-6847 cannot be rated separately ...in other words I only get one rating for all three medical issues.