I'm sorry that our heuristic filter has caught your legitimate domains.
However, changing our heuristics in the way you suggest would drastically reduce their efficacy. From very rough numbers, we'd be blocking double-digit percentages less spam, just to avoid this false positive for one subscriber.
We'd really love to eliminate this false positive, so we're working on other heuristics and filters that will be more precisely targeted. But I can't make any promises for how quickly we'll have those ready and can loosen the current filters.