If your main mast is damaged you're mission killed anyway. I'd rather have all 21 missiles, than 11, and the extra weight on a totally redundant radar.
By the way, anyone have an assessment of Meroka verses other systems? It's(relatively)low weight, low price, and very good performance stats (available to me), seem somewhat suspicious. (As does it's confinement to Spanish service!)
Its combination of proven H-S cannon, and low rate of fire per weapon seem excellent, on paper, yet very little is seen or heard of it, on this site or others I've seen.
Being 20mm undoubtedly shortens it's range, but it(range)should still be perfectly adequate for a last ditch system.