I guess I don’t understand you because I don’t understand how your point is relevant. I didn’t “forget” tax because tax isn’t relevant to the original image. It only brings up a 25% tip, and “tipping up” to a total sum is never discussed.

On the other hand, my proposed solution involves “tipping up” to a sum, which means tax must be considered if you’re going to take the time to calculate the exact tip percentage.

And also, “an excuse”? I’m sorry to ask so bluntly, but that word choice makes me wonder: do you view this conversation as a competition?