W123 Timing Chain Stretch

[tomm9298]

I need to know if I am doing this right. I turned the crank until my pointer was lined up with the pin. I assume TDC. With the valve cover off I check my cam timing marks. The spacer mark was about 1/8 inch before the cam tower mark. I continued to turn the crank until my cam timing marks were aligned. I then check my crank pointer, it was at about 20 deg BTDC. I rotated the engine 1 revolution and my cam timing marks were no longer visible, on the spacer/washer that is. I turned the crank another revolution and the cam marks were the same, not lined up. Does this mean I have 20 deg of chain stretch????