Как создать изменение коэффициента от кол-ва в калькуляторе Tilda

<script>
document.addEventListener("DOMContentLoaded", function() {
    (function () {
        const priceCard = {
                "100": "2",
                "500": "1.6",
                "1000": "1.2"
        };
        
        const calcForm = document.querySelector('.uc-calc-form');
        
        if (calcForm) {
            const st = calcForm.querySelector('input[name="st"]');
            const quantInput = calcForm.querySelector('input[name="quant"]');
            const cardcalcInput = calcForm.querySelector('input[name="cardcalc"]');
            
            if (st) {
                const stGroup = st.closest('.t-input-group');
                if (stGroup) {
                    stGroup.style.display = 'none';
                }
            }

            if (cardcalcInput) {
                const cardcalcGroup = cardcalcInput.closest('.t-input-group');
                if (cardcalcGroup) {
                    cardcalcGroup.classList.add('cardcalc');
                }
            }
            
            function getCardPrice() {
                if (!quantInput || !st) return;
                let quant = +quantInput.value;
                let fnPrice = 0;
                
                Object.entries(priceCard).forEach(([key, value]) => {
                    let line = +key;
                    if (quant >= line) fnPrice = +value;
                });
                
                st.value = fnPrice.toString();
                st.dispatchEvent(new Event('input', { bubbles: true }));
                
            }
            
            const targetElem = calcForm.querySelector('.t700 .t-calc');
            if (targetElem) {
                const observer = new MutationObserver(mutationRecords => {
                    getCardPrice();
                });
                
                observer.observe(targetElem, {
                    childList: true,
                    subtree: true,
                    characterDataOldValue: true
                });
            }
            
            if (quantInput) {
                quantInput.addEventListener('input', getCardPrice);
                quantInput.addEventListener('change', getCardPrice);
            }
        }
 
    })();    
});    
</script>

<style>
.t706__product-title {
    font-weight: 300;
    font-size: 14px;
}    
</style>