Sleep Apnea

I’m currently have 70% Major depressive disorder with generalized anxiety disorder and insomnia disorder, persistent, with medical and mental health comordidites and 30% for GERD. I have been diagnosed with sleep apnea through the VA and I have been using a CPAP. I’m currently not SC for sleep apnea, should I apply for SC for sleep apnea as secondary? I have an insomnia rating already, will it affect that rating? Thanks