I have a cal. 899 in muy Master Control with date. The only difference is that JLC manufactured this version, dial layout and case size, 37 1/2 dia., solely for its Oriental markets. Mine dates from 2011. I find that it keeps great and consistent time at + 10 seconds per day. This coincides with your article where in you state - / + 10 seconds, I view consistency equally as important as seconds gained or lost. Great article. Thanks.