How many Fraxel 1550 treatments are equal to one ablative CO2 Laser?

i had test patch for CO2 laser to treat acne scars, but the downtime with unacceptable, it took 6 months for the redness of the test to despair, furthermore, the test patch area hasn't changed at all, results is zero, so my Doctor advised me on Fraxel, i did 3 treatment, happy to do another 3, downtime almost none, i love it, results is very nice, i just want to make sure i didnt miss out with not having aggressive CO2, please assure me , and esplain to me the diffrent in results terms.