Reno Genest
Ansys Employee

It is a best practice to extend the *DEFINE_CURVE beyond the termination time. Here, the value is constant and it does not make any difference if the last point on the curve is 10 000, 1000, or 100, or even 10 ms. As long as the last point on the curve is beyond the termination time of 7.5ms. 

If you don't extend the curve beyond 7.5ms, you might run into issues. You can try it. Because, the LS-DYNA calculation will almost always go beyond the termination time. How far beyond the termination time depends on the timestep. And, for the calculation happening beyond the termination time, the LS-DYNA solver will not know what value to use and it will be reset to zero.