at the corner of flotsam & jetsam, just within the walls of reality
i don't have much db experience, but i do have an idea of what you'd like, so here goes my 2 cents (and that's about all it's worth )...
first of all, it sounds like you want a calculated field (the field departure and arrival). i'm not sure i understand your calculation, but, in any event, in order to create a calculated field, you must create a query based on whatever table (sounds like your lista table?).
after you create your query, you can either use a wizard in the form to create a tabular form. tabular will create the spreadsheet-like format you seek. (it also sounds like your form will be based on the table and the query).