+7 seconds/day is within tolerances...
Please see "faq" on the top right of pages and look for both "rate tolerances" and "accuracy after repair" (which also applies more or less to new watches).
The first section states:
[i]
The movement is adjusted in each of these positions to an average rate of between 0 and +7 seconds per day. In other words, an IWC should never be slow but may be fast by up to 7 seconds per day. The average daily tolerances for chronometer rates are between -4 and +6 seconds. This means that even a watch that loses up to 4 seconds a day can still be called a chronometer. For more information on this subject, click here.
The rate is also affected by the owner's lifestyle. The automatic movement will react differently when the wearer has an extremely active lifestyle from the way it would with a comparatively quiet person. However, any deviation from the tolerances mentioned above is not so much a question of function as of adjustment and wearing habits. [i]
Much depends also on position --usually changing postion at night will change (for better or worse) the rate. That means with trial and error you can adjust the rate.
Personally, if a watch gains 79 seconds over 10 days, but should gain only 70 seconds, I wouldn't sweat it. It won't affect your daily lifestyle --you won't be any later or earlier for anything.
But give it some time --all watches break-in a little-- and also try experimenting with positions at rest if it bothers you.
Good luck,
Michael