"Does my unique situation allow me to deduct based on cash recording method"

That's not Unique. What you describe is Periodic Inventory, essentially, and your own CPA would be the best guide for how to operate and report this info for purposes of the Fed and State.

"I am a bit troubled by this response"

Income is matched to the expenses used to generate that income. Not to everything you spend, and not everything you spend is expense. And sometimes, on the internet, some answers are provided by programmers, not professional end users. It's only a bit worse than standing around the campfire or asking while at the barbershop. Get in-person professional guidance. It's cheaper to do it right the first time than to do it over.