That is because the employer need not put on your pay stub what IT pays, only what YOU pay. Also, it has two responsibilities, reporting and paying, and the due dates for both are not consistent with the due dates to pay you your paycheck. Within reporting, it must report what it paid you and withheld from you, as well as what it owes for its own share. Within the paying scheme, it must pay payroll taxes on either a semi-weekly, monthly, or quarterly basis, depending on the level of income it generally earns.HERE
is a calendar of June, 2013 requirements, depending on which schedule your employer must adhere to. As you can see,the dates do not fall on the dates your paystubs are printed, necessarily or typically. But just as important, the employer is simply not required to inform you of to what extent and how it pays its responsibilities - only how it effects your gross pay, giving you a net pay that is less than the gross amount, so you can track where your money is going (and possibly get some back come tax return time).
I hope this clarifies! And I hope you are having a terrific weekend.