In this paper we describe a new superblock management scheme to overcome the problem of increased erase operations, that results from increasing the degree of interleaving of memory banks in flash memory based storage devices. To improve performance, superblock management is used to increase the degree of linear interleaving of flash memory banks. However, increased interleaving may significantly increase the number of erase operations, thus decreasing device lifetime. The proposed management scheme efficiently separates hot and cold data into two different sub-groups, dramatically increasing the efficiency of superblock merging. According to our simulation results, the number of erase operations decreases by around 27.3 percent, which is enough to significantly lengthen overall device lifetime. Read performance is only slightly degraded by our approach.