Did you ever figure this one out? I pressed this button too and I'm wishing I hadn't... I'm not sure if the voltages shown in BMS-Studio are correct any more :(
If you still want to reset the counter I discovered how to do it by accident last night - in BMS-STUDIO, if you go to the "switch control" tab, on the left hand side there are options to turn the charge/discharge FETs on, turn power off etc, the bottom one is called "reset system" or something -...