Simplifies tax collection process ≠ Simplifies tax code

A few lines of tax code means millions of people don't have to worry about unpredictable withholdings due to significant changes in tips from day to day, month to month, and year to year.

Also, what's sloppy about it? It's just a deduction for up to a maximum amount from tips, for a specified list of occupations, with the maximum decreasing as income increases above a specified level. That's pretty simple, as far as tax code goes. What do you think would be a less sloppy way of implementing it?