Oh mighty, invisible, non-gender specific, big entity in the sky...
...please save me from Excel absurdity such as this. While it's 'fun' to see how far to push a program with in-built coding capability (I've done it myself in Access) it's such torture to try and keep these things going because some PHB (and sometimes not so pointy) decides they actually like it and want to keep using it!
As Mr. Scott once said (in Star Trek V, I believe): "The right tool for the right job". Excel is really pretty much only for data analysis. For everything else, there's 'proper' development tools.