I have a fix pending which merges changelog entries which are _entirely_ identical, which I implemented as part of addressing bug #383803, but I gather that fix won't work here. If I'm understanding correctly, the issue discussed here is the content of the changelog entry being identical but the package name in the changelog entry (just to be clear: we're talking about the package name written in the entry in the changelog file, not the package that the entry is found in, right?) or its date being different.
Can you perhaps provide me of an example of two specific deb files somewhere I can download online which demonstrate this phenomenon so I can reproduce the issue? I suspect with a reproducible test case in hand it will be relatively straightforward to add a fix for this issue to the fix I already have pending for the other one.