$(this).closest('.product-section__information_quantity').find("input[name=count_product]").each( function (index, el) {
var allCountInform = $(el).val();
console.log(allCountInform); // отдает 50 и 1000
});
var allCountInform += $(el).val();
не решило проблему var allCountInform = 0;
$(this).closest('.product-section__information_quantity').find("input[name=count_product]").each( function (index, el) {
allCountInform += parseFloat($(el).val());
});
console.log(allCountInform);