Sharp IR distance sensor and external ADC?

Other Hardware Sensors
1

Hi,

is it worth to use an external ADC with more than 10 bit resolution with the sharp IR distance sensors? Especially for the higher distances where the voltage difference per cm gets very small. Or is the output so shaky that the 10bit internal ADC is fine enough?
Sharp IR data sheet: http://www.sharpsma.com/webfm_send/1487

Thanks
Robert