This is an interesting one.
The thing with the DF-100 is that no one really knows whether or not the missile has a seeker. The Chinese claim it's capable of hitting "large warships," so some run with that and assume the missile carries at least a rudimentary seeker to help during terminal -- and avoid situations like the ones you're encountering in your game. What we can say with certainty is that if it does have a sensor, it's probably not very good. The DF-100 is primarily a land-attack missile, after all, and if there was a more capable sensor onboard I'd expect the Chinese to emphasize general anti-ship capabilities rather than just "large warships."
A competing theory holds that the DF-100 actually performs as modelled, with no sensor. It's theoretically possible of engaging a "large warship" via inertial targeting, provided the launcher receives location, speed, and heading data from another sensor, but if any of these should change then the missile will miss. This is supported by the Chinese themselves, who were evidently waffling on whether to classify the DF-100 as an anti-ship missile or a purely land-attack missile right up until the day they showed it off in parade.
Based on what we know, and extrapolating past Chinese behavior, I think the latter theory is more likely to be correct. The Chinese government often exaggerates new weapons' anti-ship capabilities (unsurprisingly, considering how important sea control is to both the U.S. and China), and we've yet to hear anything about a seeker on the DF-100 -- which, if I was China, I'd be keen to at least mention, if that capability existed.
So, with all that said, I'll tentatively hold that the DF-100 currently in the DB is WAD. (At least until we catch wind of verifiable information that indicates otherwise.) Provided with consistent target data, it's theoretically capable of hitting a large, non-maneuvering ship. Otherwise...I'd recommend a more purpose-designed weapon.
Well，you do have a point. It still needs more evidence to prove the weapon's capability. But I would like to see any sensor added on it to make the game more challenging when playing western side against China. We can't deny the possibilty that the weapon actually got an ARH right?