Flow from the skimmer doesn't benefit you much, since it's almost always not coming out of the skimmer at angle that's gonna allow you to take full advantage of the flow. Hence I don't count the flow from skimmers.
As for 15-16 times (which effectively you have less than) turnover being to, much, well I start at 20x turnover for any tank, go up from there. Most people will tell you 10x turnover is fine for FO/FOWLR, but personally I find that the extra flow just helps so much more with filtration and oxygenation that I don't see a reason to spend the extra money to get more flow (for your tank this would cost at the most $100 to do - not that much in this hobby). Also, most nuisance algaes have a hard time colonizing in high-flow areas, meaning you won't get hit so hard when the usual algae blooms strike.