[RESOLVED] One small bug can anyone find?

[AVaughn]

One small issue. I cleaned up the code on the buttons but having an issue with stotal value.

If you compile and run this FLA, select the first then the second then the third choices then deselect in reverse till all are deselected you will see it returns an invalid number , should be zero (0), it also displays 4 decimal places, I have tried to add a function to limit to 2 decimal places but I can't seem to get it to work and even though I need that function not sure if it will fix the bad end value.