Well, it should be utterly impossible to retroactively alter the terms of an agreement once agreed upon. This just gave some wiggle room that within a given calendar year, you don't have to think too hard about the agreement as it can't change (unless you want) on you even in updates within a year.

It seems to be a pretty reasonable clause to assuage customers that while technically the terms are a living document, they can actually plan their business around the product. Giving the supplier the flexibility they want, while promising the customer the stability they may require.