See the picture. If is target and chaff in fighters strobe and chaff only in field of view, SARH go to chaff. Four missiles have different angles field of view in relation to a real target. You're wrong.
The question is, as a seeker of SARH gives priority chaff, especially if there is a secondary radio channel. What is important, is not a reflection from chaff, than dopler puls element. At the time of ejection, chaff always has the same direction (3-9 position like target), and lower Doppler effect because it lags in speed. What confuses me is bad encodedness in DCS when it comes to frequency ejection. If you throw 50 chaff per sec. it is better than 2-3 per sec. Vector between separate fixation points must exist. In reality, if you go chaff has consistently much, it can make the target even more visible. In DCS, spam with chaff pays off.