I have done this. I'm just honest with myself that my streaking is costing me XP, especially when I do really silly things like try to flag for LOB/MA on Elite massively underlevel and solo.
But if a quest or raid comes up that I will be doing lootruns of at 20, I don't hesitate to break streak to do it immediately. Unless doing it at 20 would take appreciably less time than doing it at say 17, I'm getting some XP for no time investment at all.
One character wanted an Omniscience (and VOD elite is not really PUGgable and I don't have many guildies/friends that still need anything from there), so I broke streak to run the raid on Hard. The same toon wanted LOB completions, so again, I broke streak to knock out a Normal or Hard one, and I think they might have even done an MA for laughs.
VOD is extremely good XP if you were going to be running it at 20 anyway.
Running it at 18 - 20k XP award (+some negligible amount from slayer area), ~7k XP in missed bonuses on future quests = ~13k total for your ~30 min.
Running it at 20 - 0 XP for your 30 min.
So for no time investment at all (as you were going to run it at 20) you got 13k XP. In IQ, getting 13k XP takes at least 6 or 7 minutes (realistically more in most groups).
Of course if I didn't want to run VOD at 20 I wouldn't do it unless I wanted a break from the extremely boring IQ and Refuge.