Hi, this is how Airbnb works,
You cannot breakdown deposits, it is one fixed amount per listing for everyone regardless of duration of stay. The deposit is not actually paid upfront by the guest; Airbnb only collect the cost of booking plus any service fees upfront. If there are any damages caused by the guest then you can claim against their security deposit at the very latest 24 hours after the guest checks out.
The nightly price seen by each guest on the search page will only be different to your base price per night, if you have additional fees such as cleaning and extra guest. When a potential guest does a search, the price per night they see will depend on the duration of their stay input into the search engine i.e., if I search for 2 nights, the price I see per night may be different to another guest searching for 4 nights - this is because the nightly fee is based on an average of the combined fees as charged by the guest, this is also a more accurate price of what the guest will end up paying – see formula for calculation
Number of nights + cleaning fees/ additional guest fees if applicable = total cost / number of nights = true cost per night.
So long as you set any discounts in the Price Settings this will be triggered automatically once setting reached
Re other hosts deposit, speaking for myself, I set a fixed deposit which is based on any minor repairs/ replacements i.e., replacing door locks as a result of guest losing keys which is a common one, damage to ornaments/essentials (towels or bedding) minor which would cost me to replace as a result of damage. My deposit on Airbnb is based on the type of bookings I accommodate. I only do short lets and I live in the property so I can oversee their use so there is less risk for me which is factored ito my max deposit. However deposit charged on my entire lets is higher as due to more exposure to risk.
You need to assess you properties individually and decide what is realistic. To combing your example with my explanation, I charge a one night stay the same because if they lose my keys, it would cist me the same to replace my locks as it would if a guest staying 10 nights misplaced my keys.
The security deposit has no impact whatsoever on the price seen in the on the search page. The guest only sees it once they click on you individual listing and to be honest is should not deter them really; if a guest plans to be respectful of the host's property then they have nothing to worry about since the deposit will never be deducted.
BW, Ama
