For \(0<w<1\) and any integer \(t\ge 1\) , let \(E_{w,t}\) be the least integer d such that for every set A of nonnegative integers with the lower asymptotic density \(\underline{d}(A)=w\) , the set \((k+t)A\) contains an infinite arithmetic progression with difference at most d, where \(k=\lceil w^{-1}\rceil \) . When \(t=1\) , Chen-Yang-Zhao have given the asymptotic behavior of \(E_{w,t}\) . In this paper, we generalize their result and prove the asymptotic behavior of \(E_{w,t}\) for \(t=O(k\exp (-1.5c\sqrt{\log k}))\) , where c is a positive integer.