Prayer Times Angles
I don’t get why it’s not a problem. The specific times should have been exactly that- specific. The prophet صلى الله عليه وسلم prayed at one time not one time one day and another another day. There should only be one right way. Especially factoring in tawattur
If you consider geographical location then it will change. Read this pdf for understanding method of calculation you will understand factors involved in calculations. Remember these models are generalized based on approximation and interpretation.