1. Please be so kind AS to: is AS obligatory? In this exact phrase, yes. 2. The REGARDING amount: regarding: authentic wording? No. Alternative word depends on context. 3. As soon as the parcel ARRIVES/ HAS ARRIVED Either is acceptable 4. ... arrived IN/AT the warehouse? Either is acceptable 5. on your own cost: authentic expression? Doesn’t ‘at your own expense” sound better? Yes it does. (AT replaces ON in the original expression)

2. The appropriate amount, the said amount? Use appropriate if there are options to choose, use said when there is a specific amount already calculated 5. ‘Cost’ isn’t authentic either (?) At your own cost or At your own expense mean slightly different things to Accountants but are often used interchangeably by most people, which is perfectly fine.