Any chance of adding additional resistors to the CellMons for extra discharging balancing?

No, you cant add additional resistors to LongMons, BMons, LeafMons or other Cell monitors. When designing the BMS the total balancing power need has to be planned for all components, Over the last +5 years we have seen that 8W is enough for most scenarios and when more is required (> 400Ah) we double up the cell monitors.

The theory behind this is that what is happening with balancing is the different cells in your battery pack with passive balancing is that cells that have reached the bypass voltage burn off extra power (to prevent overcharging and lower their voltage and allow other cells to catch up) This is done by using resistors to release heat.  However our cell monitors are only designed to handle a certain amount of this, they are not designed to balance constantly and the extra heat will eventually damage the board reducing it's lifespan.  Adding extra resistors would only make them fail sooner and maybe immediately.  A better way to improve your balancing power is to add a fan, triggered by bypass state or temperature, the flow of air will cool the bypassing cell monitors greatly increasing their bypass power.  Another option mentioned above is when more is required (>400Ah) we double up the cell monitors.  Please be aware that doubling up on your cell monitors doubles your parasitic load and once your battery pack is in control is probably no longer necessary.