Yes the 50% rule is not set in stone and you can go below that without penalty an RVer (with few cycles in a year anyway on average)would ever notice.
My reason for staying above 50% before recharge has nothing to do with battery life, but relates to the voltage drop at 50% SOC still keeping voltage above 11v inverter alarm with my four 6s. Since low SOC is in the early morning when it is time to make toast with a real toaster using the inverter, I have to stay above 50% "morning voltage" or no toast :(
PT with his 12s could go down to 35% SOC and still make toast if I understand that about 12s vs 6s. :)
