With patreon donations the amount you got charged the amount you will receive according to Pricing page. By upgrading tiers you will not receive the amount it says.
Make sure to cancel your membership on Patreon after you get your cash
How do I donate again if I already sub to one of the tiers ?
Hover over your profile photo from the top right to click the “Manage memberships” link from the menu
Click the “Edit” link in the membership details for the membership you’re changing.
Click into the “Choose what you pay” text box.
Enter your new payment amount – your new payment amount must be equal to or higher than the minimum price of your current tier.
You need to add the value you want to donate in the text box. Meaning if you click update without changing anything it will not charge you, if you add lets say 10$ on top of the current value it will only charge you with the added value not whole value again.
In right side you will see "Today's Charge" that is the amout you will be charged and cash will be given depending on that.
Click the “Update” button. Also be sure to cancel membership after payment in order to not be charged again next month.