Good points UAZ.

There is also the issue of settings for the missiles themselves.

One of the problems for the SA-2 in for example downing B-52s or for that matter other types, was that it was found that the proximity fuse settings were a bit optimistic regarding the effectiveness of the warhead and the accuracy of the guidance. Although fitted with a very large warhead they tended to explode to far from the B-52s to adequately destroy them… something the US was very keen to keep from the Vietnamese and Soviets of course. Jamming and decoys increased miss distances which meant firing more missiles was a reaction but not necessarily a solution to these and other problems.