I have a 2220.80 Seamaster Bond Coax. I had it serviced about a month ago by a local watchmaker. Watch runs fine on my wrist. About -2 per 12 hours during the day when I wear it. Then the 12 hours it sits at night, it'll loose 10 seconds over 12 hours??? Even if I manually wind it before nighttime. Does this on its side and face up... I hates being put away for the night!
I suppose it might be possible to suggest a number of reasons as to why your watch might behave in such a manner. But it is on your watchmaker's bench where the cause is most likely to be found.
The daily rate of your watch is always the average of 5 to 6 positions. It's most likely that the positions your leave your watch in at night have a lower rate than when you wear it (which varies greatly depending on your wear pattern).