Don’t know if you’re referring to Scuba Schools International (SSI) which is where I got certified. We dove in water of various conditions and depths and my last requried dive was a test of underwater navigation. (I’m still not as good as I’d like at that.) Admittedly, it was a number of years ago, but a couple times (maybe 3) when I’ve called ahead to dive operators, they’ve made comments about preferring people trained with SSI.