You lose precision as normal TF model by default uses higher degree of precision for calculations (unit32) however post conversion to TFLite, it becomes slightly lower due to conversion of values to (unit8). As far conversion from H5Model to TFLite, that’s the way it is. I shared my personal experience, so accuracy will drop with TFLite but sole idea behind TFLite is to give inference using edge devices like Rasp Pi , Coral TPU etc, so its a tradeoff.