Sales levels in the Hamptons housing market slid year over year for the first three quarters of 2018 as price trends were choppy but generally moved higher. Average sales price rose 5.8% to $1,774,043, and median sales price increased 8.4% to $965,000 respectively from the same quarter last year. However, the critical metric of focus was the decline in sales. There were 448 sales in the quarter, down 13.3% over the…