When PQM is put into RC-only mode it should still process branches that were submitted before it went RC-only

After having four branches, which were submitted well before the non-RC window closed on Sunday evening, bounce because they weren't marked as RC, I've been thinking: Why does going RC-only work the way it does?

Here's the way I currently see the process, from my admittedly limited point of view as one of PQM's frequent victims:

 1. Friday, week 3: I submit a branch.
 2. Saturday, week 3: It bounces, possibly with a comic "twang" of someone's
 braces snapping.
 3. Sunday AM, week 4: I resubmit it.
 4. Sunday, 19:00 UTC, week 4: PQM goes RC-only.
 5. Sunday, 19:01 UTC, week 4: PQM processes my branch, and spits it back
 because it's not RC only.

They way I see it, PQM should work like this:

 1. Friday, week 3: I submit a branch.
 2. Saturday, week 3: It bounces. Hilarity ensues.
 3. Sunday AM, week 4: I resubmit it.
 4. Sunday, 19:00 UTC, week 4: PQM goes RC-only.
 5. Sunday, 19:30 UTC, Launchpad developer Joe Soap submits a branch for
 processing.
 5. Sunday, 19:31 UTC, week 4: PQM processes my branch. Miraculously, it
 merges.
 6. Sunday, 20:51 UTC, week 4: PQM processes Joe's branch. Because it was
 submitted after the RC deadline it isn't valid and gets rejected.