You can write them direct in the table or from an internal table with an update/insert/modify statement. Both options are possible and it all depends on the rest of your code what would be the better option.
About the include. This include is then probably used in both programs, isn't it ? That would be no problem since you are writing it to a custom table that will be accessible from both programs.
One more thing. Is the key sy-datum and shipping point enough to uniquely identify the entry you need to pick up in your second program ? I don't know the scenario but you might want to add the document number (order, booking) if you are dealing with documents. If this is purely master data then it would not be necessary.
Imagine that the program is running simultaneously for two orders with the same shipping point. Would you still be able to pick the right entry ? Ask yourself this question (in the context of your program coding), so you will be sure to pick up the right entry and you are sure you can uniquely identify the correct entry.