I have my settings at “Start Charging” at 75% SOC and “Stop charging” at 40% SOC. If I connect EVCS to car at less than 40% SOC, it begins charging once 40% SOC is reached. Victron please fix this in next firmware upgrade. (I’m running 2.08.)
Are you using Auto mode?
Start charging at backup battery SOC: The minimum backup battery SOC before the EV Charging Station NS starts charging in Auto mode.
No. I’m in Manual mode.
This is working as designed. As @AhtiH covered above, the “start charging at SoC” set value only applies to auto mode, when in manual mode the SoC must be equal to or higher than the “stop charging at SoC” set value. So it makes sense that if your charger is in manual mode that it will start charging once the SoC reaches 40%.
If you want the EVCS to instead start charging at 75% then set the EVCS to auto mode 
Got it. Thank you.