For now, we're advised by Cedric that the Security deposit is not included in the total amount on the order page but when guests click Book now button > lead to process the payment > they will need to pay the correct amount with SD included. The reason why we don't include the SD is to avoid having a large total, but guests still need to pay for it.

That is not an acceptable reason as it's still misleading to the guests. Why include the SD in the breakdown if you're not going to include it in the total. We are not trying to hide anything from our guests and we want it to be transparent as possible.