Your payslip shows what leaves your pay. Your pension statement can show something different: your contribution plus tax relief and money from your employer. Start by comparing those two records.
This lesson concerns a defined contribution pension, where contributions build an invested pot. A defined benefit scheme promises benefits using its own formula; do not apply the pot arithmetic to it.
Ask payroll what earnings the percentages use, what the employer contributes, and whether paying more changes that contribution. A legal minimum and a discretionary match are different arrangements.