[MazdaMatt]

My foot is at 20% throttle and the current sensor reads 15% of max current. It then takes the error and multiplies it by the proportional constant Kp and adds the previous error plus the new error *Ki, adding the result to the current PWM output in an effort to generate a 20% reading from the current sensor. Hense, PI control.

PI, PID, P Control does not have to specifically relate to speed or position control. You could use it in business to set prices based on buyer demand (Kp) and buyer backlash (Ki). You could use it pressure control systems with valve actuators... anything really. You take in two values, scale them, subtract them to get an error value, then modify your output to try to get that error to zero. It is a very generic term.

edit: the system would not require PI if it had a speed sensor and a prior knowledge of the relationship between speed and current per dty%.