...and here I thought only the BVA was capable of ignoring the law and making really stupid decisions. Clearly this decision is contrary to law. The Code of Federal Regulations mandates a 50% award for a diagnosis of sleep apnea with CPAP. Whether you work or not is irrelevent. This is the prime reason an appeal system exists.
File a Notice of Disagreement with the RO and ask for a deNovo review. Just write a letter to the RO and state your name, SSAN , Date of Decision and what it is you disagree with. Follow that by asking for a deNovo review.
Sleep apnea is evaluated under
38 CFR §4.97 Diagnostic Code 6847 where it says in part:
6847 Sleep Apnea Syndromes (Obstructive, Central, Mixed):
Chronic respiratory failure with carbon dioxide retention or cor pulmonale, or; requires tracheostomy 100%
Requires use of breathing assistance device such as continuous airway pressure (CPAP) machine 50%
Persistent day-time hypersomnolence 30%
Asymptomatic but with documented sleep disorder breathing 0%
You don't need a lawyer at this stage. Just file the NOD with request for deNovo review. If they fail to give you a full grant of request, they'll send you a Statement of Case (SOC) and a form 9 to request an appeal to the BVA.