I think the mass of the grate design provides a few things that offer an opportunity for movement about the frame ... i.e. the ability to move away from the "450" and yet the "450" being strong enough to have us come back to it.
There is oodles of symmetry / rhythm for exploration. There is also the directional flow of the vanishing line / diminishing size of the grating. And again, once you get to the end of the line, there's the mass and tonality (and numeric) of the "450" to return your travels. In that regard, there is opportunity for movement which lets you go "to and fro" ... never really getting "stuck" in a single place.
For some, the concept of balance is about centricity and / or symmetry. For others there is the matter of asymmetry. The components that move the eye can be "things" or they can be relationships, implied lines, and a host of other aspects of compositional elements.
There's also the matter of static balance ... where things just kinda "sit" in a place that really is about "counter-balancing". This is in contrast to the concept of dynamically balanced, wherein the movement can have a greater life span to it ... yet, nothing is so strongly weighted that one gets "stuck" and cannot resume movement. Asymmetrical / dynamic balance can offer tremendous movement opportunity. Of course, if one's goal is to induce a "fixed gaze" to a given point, then the approach to balance / counter-balance may be akin to a means of "framing" also.
Point being ... there are a variety of ways to achieve balance, and there are different kinds of balance depending on your goals for whether you want your viewer's attention to be more "fixed" (static) vs. more "movement" (dynamic) oriented.