Issue on setting prices for separate dates

Hello,
Another question is the following:
when the regular price is set and after I set a separate discounted price with extra services a6lso discounted it is adding extra price on the date discounted price although I didn’t note with checkbox for the extra fee.
How to make fixed that? or that kind of booking system isn’t recognised checkbox even it isn’t noted? I mean all the dscounts a6re plused with each other and then calculating?
if it’s so then why calculate all together if I want to do discounts both on the main tour price and the extra service by setting there an option customers want to take or not? in fact the system automatically calculate the extra fee too.
how to fix it?
from the screenshots will be clear what is the issue on.

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