I believe this sale was the highest thus far. Green River 9.0 for 24,500.00.
http://www.highgradecomics.com/article.php?dynamic=gallery&id=2&sort_by=PROMO_PRICE
The last 7.5 in December also made a 1k leap over the last reported sale. They still seem to be climbing.
Between the last 90 days, the last 4.0, 5.0 7.0 and 7.5 as well as the 9.0 GR have all been broken so there's still movement upwards even if its not by a lot, it's still heading North. Makes you wonder what else has been sold out there that's been over the GPA highs in each grade.
I agree though, while gpa is a useful tool at times, it does lag behind a bit.