Need some advice

[hey_moe]

I have a 12x24x52 AGP, my problem is when I ordered a liner they told me to measure the outside wall to determine the size. From outside it is 52 inches from top to bottom. Anyway after the build and adding in two inches of sand I installed the beaded part up at the top and from the beaded to the bottom of the pool it was 48". When I contacted the company I ordered the liner from they said as long as the outside pool measured 52 inches I would be fine. Even after telling them that the inside measurement was 48 inches to the beaded insert they still said I was ok. Are they telling me right?