The system calculates delivery for each item separately

-- url of the page with the problem -- : www.politikchronist.org
-- HikaShop version -- : 4.4.4
-- Joomla version -- : 3.10.3
-- Browser(s) name and version -- : Firefox 94
-- Error-message(debug-mod must be tuned on) -- : How to make the system cumulating delivery cost of different items

Hello,
when ordering 10 pieces of same item, the system calculates correctly the correct delivery with the relevant allowed weight.
But when ordering 2 different items, the system does this for both items separately.
Sorry, did not find the switch ...