A system and method for managing data writes in a non-volatile memory including SLC and MLC blocks of non-volatile memory and a MLC block health rating data structure tracking relative MLC block health. A controller in the system may be configured to select MLC blocks for receiving host data and then route the host data over a direct MLC write path for healthy blocks, or over a two-step indirect write path that includes a SLC write and a SLC-MLC fold for unhealthy MLC blocks. The method may include assigning a health designation based on BER determined for each MLC block and assigning a direct write number to healthy MLC blocks based on the determined BER that limits the number of program/erase cycles for direct writes for a particular MLC block until a re-assessment of block health is needed.