Looking for a practical way to confirm my season

I am new to checking undertones without an appointment but my results change more than I expected. In indirect morning light my skin seems neutral to cool while warm indoor bulbs make it look noticeably golden. My phone also applies automatic white balance even when I keep the same position and background. I have removed makeup and used a plain gray shirt so clothing should not be adding much reflected color. I am comparing the photos with a simple [url=https://hairdye.top]skin undertone test camera[/url] rather than trusting one image. Is a fixed exposure and white-balance setting essential before taking a short series of photos? I could place a white sheet and a gray reference beside my face if that makes the comparison more useful. For anyone who has compared camera tests with an in-person result, which lighting conditions were consistent, and which clues did you ignore? I am mainly looking for a method that produces the same answer twice before I start choosing hair or clothing colors from the result.