factors coming in to play. You can still get excellent results with calibres containing regulator pins, it just takes a little longer. I have sometimes seen better timing results from a 1520 (pins) compared to a 1570 (free sprung), it just depends on how the pins are adjusted. You have to make sure the hairspring is completely centred between the pins (hairspring not touching either pin) with balance in resting position. Then you have to adjust the distance between the pins so that the rate is similar when the watch is running at both fully wound and at half wound. This is because the amplitude will reduce at half wind. If the rate drops at half wind, you have to close the pins a little then test full and half wind again. Another indication is if the rate drops a lot in vertical positions because the amplitude is lower. Once again, reduce the distance between the two pins. Of course, there can be more factors that come in to play but this is the basic idea. With everything set-up perfectly on regulator pins, I have seen a rate difference of less than 5 seconds in 5 different positions. I have even seen it as low as 2 seconds difference.