Even with optimizations, if you keep your backend same same code with same flag will return identical binary (modulo datetime and file location being for some reason embedded).

Same query to same AI, at different times of day will might not return the same answer. For example I wrote some docs for a class that had 14 methods. So I asked for autocomplete docs in 2 methods, and it followed other method comments well well. Then I asked to do the same task for 2 more methods and it fucked up, requiring manual edits.