It creates a reusable function that takes three inputs: actual sales, sales quota, and a weighting factor. It returns a ...

Performance becomes an issue with large datasets too. A poorly written macro can bog down Excel and take forever to complete, ...

Why? well, because it falls over helplessly when anyone attempts to use it as a database. It's really not queryable. Because it's impossible to audit. Same formula in all 3700 rows of a column?