Climbing numbers are a can of worms, where there's basically no such thing as a real answer, even if you discount inaccuracies, fluctuations, and unknown smoothing algorithms, and imagine you've got a hypothetical 100% accurate altimeter.

It basically comes down to how high a climb has to be before it counts as a climb.

The smaller the climb you count, the larger a climbing number you'll get. Just work out what number you would get if you counted every mm climbed over ever bit of gravel chipping along a whole route, even if it's pan flat along the cide of a canal.