What's the problem with the cupholders?

Hey, poker room managers: I have a question for you.

What is so damned difficult about matching the number of cupholders that you have built into your poker tables with the number of players that you seat at each table?

It seems to me fairly obvious that the optimum arrangement is 1:1 matching. That not only makes it clear whose drink goes where, but provides a simple, visual reference point for squaring up the table (i.e., getting everybody equally spaced): you ask every player to center himself on his cupholder.

But in roughly half of the places I play, there is a discrepancy. I have seen 9-handed tables with 8 or 10 cupholders, and 10-handed tables with 9 or 11 cupholders. This occasionally leads to somebody not having one and setting a drink on the felt, which inevitably spills, making a mess. It also leads to people accidentally swigging the wrong drink, petty disputes about who gets to use which cupholder, etc.

I don't get this.

If you've decided to seat your games with ten players to a table, how about buying tables that have ten cupholders? If you've decided to seat your games with nine players to a table, how about buying tables that have nine cupholders? Is the math on this situation just too hard for some of you?