I think that's part of how English verbal modes include strong distinctions between relative times of actions and continuing actions. (Compared to, say, Japanese, where it's hard to indicate what happens in "After we ate, I had cleaned the dishes, and was puttering in the kitchen" except as a simple sequence of events, without a lot of verbal gymnastics. Contrariwise, Japanese verbal modes make it easy to indicate how well one knows whether the action happened, which can take a string of auxiliaries in English.)

---L.