Brightness 13 pro vs 17 pro

Dear friends. I visited, since Friday the 19th, 3 stores here in Athens (Plaisio, Public and Kotsovolos) and compared my iPhone 13 Pro with 17, 17 Pro and 17 Pro Max. 3 phones in each store. That means, I compared my iPhone 13 pro with 9 different new iPhones (17). Very strangely, my iPhone 13 Pro had the best brightness of all. The settings were all the same, that means, no True Tone (deactivated) and no Auto Brightness (deactivated too on all phones, mine and the rest). The employees on each store saw that my iPhone was brighter and couldn’t explain it. All iPhones, mine and all the 17’s run IOS 26. Do you have any explanation about that. I am interesting in buying the new iPhone 17 Pro or Pro Max but brightness is important and this keeps away from buying the new one. Thank you.

iPhone 13 Pro peak brightness 1.200 nits

iPhone 17 peak brightness 1.600 nits

iPhone Pro/Max peak brightness 1.600 nits