[рони]

Dolf,
пробуйте...

$(function() {
            let index = 1,
                max = $numBuild,
                length = $countBuildings + 1;
            const hideCells = _ => document.querySelectorAll("#ex4 tr")
            .forEach(({ cells }) => {
                [...cells].forEach(({ style }, i) => i && (style.display = i < index || i >= index + max ? "none" : "") )
            })

            var text = [...document.querySelectorAll('#ex4 tr td:nth-child(2)')].map(({childNodes})=> [...childNodes].slice(-2));
            const textMove = index =>  document.querySelectorAll(`#ex4 tr td:nth-child(${++index})`).forEach((td,i) => td.append(...text[i]))

            hideCells();
            textMove(index);

            $(".scroll-table").on("click", "[data-up]", function() {
                index += +this.dataset.up;
                index = Math.max(1, Math.min(length - max, index));
                hideCells();
                textMove(index);
            })
        });