Techno~: Question Regarding Attack/Decay's Relation to Amplitude

Hi, when experimenting with the techno~ object recently, I found that attack/decay values exceeding 1.0 made amplitude a higher value than what it actually is for a given step. Now, I understand that the attack/decay values determine the exponent for the line connecting one amplitude value to another, but shouldn't the given values never exceed the value of amplitude at a given step? I picture it as the exponent changing the shape of the line connecting two points, but never by so much as to make that line jut above the point it is heading to. If i were interested in limiting the values of attack/decay so as to prevent them from causing amplitude to exceed its value at a given step, what limits might I want to set to the attack/decay values?

If anyone wishes to test this out for themselves, here is a patch I amde that allows you to easily adjust the values for amplitude, attack and decay: