"Hiding income!" Sheesh, you guys catch on quick!
Overhead tends to be close to a certain amount unless you make some unusual payments in a given month, as Feli said. If your overhead stays the same but you make more, then your overhead percentage goes down.
Also, just because your business made more money, it doesn't mean you have to pay yourself a higher salary. You can leave it in the business, as narkotiks said, but you can do it legitimately without buying a new company Porsche or remote "business office" in the Bahamas. You can just leave the money in the business account. You don't have to spend it.
If you do not need to pay yourself more, then why do it? With every paycheck you also have to pay social security tax, workers' comp tax, FUTA, SHOULDA, WOULDA, COULDA tax and all sorts of payroll taxes, some of which I don't even know who's getting. Keep the money in the business account, and when you need it see if you can make it a business expense and avoid the payroll taxes.
As a private corporation you pay yourself a salary, but you also pay yourself dividends. So say your business made $125,000 more than the previous year, you might only bump your salary by $12,500, but then take more dividends each quarter.
Three things you all need as a business owner: a lawyer, an accountant, and a banker. Get to know each of them very well.