Thanks TomGeorge, but I really would likely not have jumped into this conversation if I had noticed by your profile that this is a specialty of yours.
I do agree about the crossing of wires. Anything switching can create a lot of interference, and is often best served first by preventing such crossings or even closeness, and then additional means such as the caps, movs, whatever. Not sure, but I'd guess those ballasts create quite a surge - perhaps switching to electronic ballasts may be a good idea, but kind of a hassle I suppose, as well as an expense that may be avoided if all else is done correctly.