you've just hit on an unavoidable disadvantage of having to locate drivers covering two frequency ranges in a horizontal relationship, as you do with vertical arrays of large numbers of drivers.
The lobing which normally is heard in a conventional vertically oriented two or three way when moving the listening position up and down is now heard when moving the head left and right. In essence, the tone changes as you move across the front.
There can be only one reference axis - i.e. point at which the tonality is correct and frequency response curve maximally flat. The response becomes less linear either side of that. In a typical line array with flat baffles, the acoustic centres of the drivers are more likely to be equidistant from the listener if the tweeters are to the outside, especially if the midwoofers are cones.
You should also ask the manufacturer what the design axis is for those particular speakers.