I'm curious why it makes no sense. Let's say you found a piece of evidence (and it was a sub-team of EPCSO) and it had fibers on it. You don't know that when you collect it. Some of the fibers match known objects in the house (carpet) but others are specific and appear to come from clothing - say from underwear. You really want to know if that fiber is found in the house (in the laundry, in the underwear drawer, etc). You go back.
That leads you to another inference. And more testing. Perhaps you didn't expect to find DNA right where you did (on that first piece of evidence - which was not sent for testing because you have hundreds of pieces of evidence and no budget for testing every single thing - especially fast tracking it).
You realize that some person (perhaps someone unknown to you) has been in the house - a lot. You now know whose underwear it is, but you also know something else.
Etc. I'd want DNA swabs from all the appliance handles, if that were the case. The medicine cabinet mirror/door (perfect place for fingerprints too but those have probably been looked at - but DNA swabs weren't taken because no reason to spend $$$ just yet). All of the entrance and exit handles (you know the family touched them - but did this new person touch them too? Big tells in that).
I'm of course just making this up, but there are literally hundreds of scenarios in which we have to go back to a crime scene again and again.
In one real world case, forensics found out there was drug residue (meth) on some objects in the house and did several passes to find more traces. I visited the crime scene on about the 5th pass, looking for unusual places that drugs might be stored, but also for some other clues (we knew who the drug user was and no one wanted to literally tear the whole house apart, we wanted to find hiding places). We did find a small stash of meth (they'd already found weed and paraphernalia) but in addition, we found other, more important evidence (of a symbolic nature) as well. I have no idea how many times LE was in that house, but it was many times. They found all sorts of things over time, not all of them related to the particular crime we were investigating.
So I am VERY optimistic about today's development. Where I work, the investigation vans do not have such clear markings. And I've seen LE swap vehicles to throw people off, when doing work out in a particular neighborhood. They're not trying to hide the fact that there's a criminal investigation unit on Mandan Drive today.