Final Value Fee Cap (Basic Store Subscription)

[bigdaddymoon2]

I am considering upgrading to the Annual Basic Store Option.  Dumb Question... The $250 Final Value Fee Cap means.... The most I would pay in selling fees for the month, reguardless of my sales? Is this correct. My Sales are increasing and the last two months I will have paid 620$  this month already 670$+..  Trying to keep more of my $.... Thanks for anyones time out there!