So what you're saying is your spreadsheet that has a single guy looking at it to find potential issues or bugs is more accurate than retail software that has thousands of guys looking at it or live data feeds updating greeks in real time?
Learning something new every day - you may want to sell your knowledge (or spreadsheet) to these retail platform companies - I'm sure they would save a lot of development $$$ and end up with happier customers
That's not how it works. I know the guys at TOS, use to spend time in their office in Chicago. I know their developers too since I've worked with them. They are just using standard off the shelf stuff that is not terribly accurate and the avg weekend warrior retail trader is more interested in colorful charts and alarm bells then dedicating more resources to option pricing which 99% of members of this board don't even have a foggy clue about it. It's a resource allocation issue. I'm glad you could learn something today.