An expression that adds up

If you start by subtracting the layer's inPoint from the time, then divide that number by the interval and use Math.floor() to keep the value a whole number, you will get an even number multiplier you can use to add that value to a starting number. The expression is fairly simple. Add it to a text layer/Text property and you have your counter.

t = time - inPoint;
count = t / .5; // interval time in seconda
num = Math.floor(count);
step = 88 * num; // value increase
strt = 23604 + step; // starting Number
result = strt + "kg"

To keep the numbers from bouncing around, you will need to use a monospaced font like Courier;