Eight scallops and a lobster cost 2420m and is subject to ongoing attrition. This doesn't seem completely unreasonable.
Three scallops and a lobster is 1120m. There are a lot of unit combinations for this amount that can kill coms. Riots in general should be pretty good against commanders, especially ones like scallop that are single-target.
Is scallop/lobster strong? Yes. Is it broken? Maybe. Are the above examples proof of this? I don't think so.
IMO the broken aspect of scallobster is that it breaks the RPS triangle meaning the counters are very specific.