The log entry "Online shop difference" means that xentral has detected a difference between the order total from the shop and the calculated total in xentral. Then, to be on the safe side, the checkmark "enabled for autoshipment" is removed. If such a case is only due to small rounding errors or similar and you don't want orders to be held up by this, you can set a tolerance range in the shop interface.
To do this, go to Administration → Online Shops in a shop, go to Details → Settings, check the "Set total amount" option and set the maximum difference from the amount (e.g. 0.05 = 5 cents) within which autoship should be allowed:
This is also useful for orders to Switzerland, where prices are now often rounded to amounts of 5, 10, 15 etc. Rappen.
You can find more information in our manual: