4 probe method for resistance

It turns out that the regular method that I use for measuring resistance is called the 4 probe method. In this experiment I am running current through a wire and measuring the voltage. As I change the length of wire, I adjust the potentiometer to keep the current the same. I measure the voltage each time and divide by the current to get the resistance. I was taught the method many years ago by a wide older colleague who said that the constant current keeps the temperature of the wire constant and eliminates it as a variable. This must be true. But in the 4 probe method, the current is kept constant to eliminate the effect of contact resistance. In the 2 probe method, the voltage is kept constant whilst the current is varied. The current flows through the contacts and there must be a potential difference across the contacts which means that the voltage recorded will not be the true value. As the current changes, that potential difference will also change since p.d.=IR. In this 4 probe method, no current flows through the voltmeter if it has sufficiently large resistance so there is no contact resistance p.d. and the voltage recorded is true.