I'm not OP, but one way to reason is that he's not competing with $.99 fart-apps, but rather with an expensive specialized medical devices. From this perspectiv

I'm not OP, but one way to reason is that he's not competing with $.99 fart-apps, but rather with an expensive specialized medical devices. From this perspective $199 is a very reasonable price point. Maybe he could charge even more for that, but it depends on what feedback he's getting from his customers.