Thanks for the suggestion, Molon Labe--and d'oh!
SUBROCs work like a charm now. I found the problem: it's a classic case of the PICNIC Syndrome (Problem In Chair, Not In Computer)

. What happened was that I discovered the problem while I was still using stock. Then I found LwAmi, and
then I found the chart. Resolving to test out the SUBROCs using the splashdown charts, I did so, not knowing that LwAmi had gotten it already...
Most of problems nowadays were caused by me shooting from the NAV chart. (Wasn't using FC autos, but I didn't manually set the ranges.) After I set the ranges
manually, of course, splashdowns and kills. I suppose this means the AI likes to fire off their rockets without verifying their solutions, but eh. Still, I've yet to see RBUs used to good effect.
Time to terrorize those Imperialist Dogs/Western Infidels/Renegade Russians...
BTW, since we're on the topic of ASROCs: anyone notice that the AI likes to use them even in littoral waters? Nearly laughed myself to death on the ASW Penetration mission (comes with the game) when the Spru-can rippled off a barrage of ASROCs in 25m water. (And VL-Asrocs should have 28nmi range, unlike their non-VLA counterparts.)