So, I bought the new Longines HydroConquest about 10 days ago and was tracking its movement with the app WatchCheck since I bought it brand new from AD. I can say that I am extremely satisfied with the accuracy of the watch. It’s early days yet but I can say that my watch lost about 17 seconds during these 10 days. Interesting, the watch is the most accurate when it is on my wrist. It is a little fast but when I rest it at night it slows down. The one position it gains is if I put it face down. So, I believe I can control the accuracy of the watch putting it in different position during the night. Even up to few seconds deviation per month.
I am including the screen shot of my results.