Understanding Salary Grade and Step: Bakit mas mataas ang sahod ng anak ko kesa sa akin?

Q: Im a Supply Officer I of our school. Im a salary grade 10. My salary is 19,000.00 working since 1981 as government employee. My daughter applied at DepEd 2018 happy to say she avail 1item permanent as ADAS. Her salary is 18,000.00. I wonder why my salary is very small compare to my daughter.i already render in govt. Service for 38years more or less. Im a civil service eligible. Can you explain to me maam and sir for this matter?