FWIW the human palate can really only taste up to 60 IBUs anyways. Any time you think a beer is more bitter than that what is really happening is that the hop aromas and flavors trick you into thinking there is more bittering compounds in the beer than there really are (or tricking you into thinking you can taste more bitter than the 60 IBU threshold). You take two beers that have the same lab-measured IBUs, but one also has a ton of flavor and aroma hops and the other only used bittering additions, you'll identify the first beer as being more bitter even though they technically have equal amounts of bittering compounds.
Also curious to see how they got 658 IBUs into a beer since my understanding is that it is really tough to get the bittering compounds in hops to isomerize into the wort much above the 100-120 IBU range using traditional brewing methods.