Really?!?!
6%

I tip more than 6%
6% is not an incentive. more than a few dozen threads have suggested and recommended the value of cents to players. When you lower the price to meat those expectations, then sales will shoot through the roof.

A lowsy 6% is almost an insult for a "sale"

I will admit that at least you are trying something. That is to be commended. But I think you are going to offend more people than you entice with this offer.