I mean that if you think of the CIT points as being the X axis (or independent axes if multivariate) of a contract, the Y axis is the dependent variable represented by the CTV hashes. 

For a DLC living inside a lightning channel, which might be updated between parties e.g. every second, this means you only have to recompute the cheaper part of the DLC only if you update the payoff curves (y axis) only, and you only have to update the points whose y value changes.

For on chain DLCs this point is less relevant since the latency of block space is larger.