"Not horrified" is a pretty low bar, but at least you've got something that's drinkable.
If you like it, great. If you don't, there are plenty of things in the recipe that would point to an out of balance, out of style beer.
First, the OG is low for a DIPA and, yes the hops are off the chart. Very bitter for a beer of 1.061 OG would be anything over 100. For IBUs as high as you have, I'd be looking for 1.100 or higher to even come close to providing the malt and body needed to offset that sort of bitterness. The Chocolate seems out of place and the high percentage of Acidulated is puzzling. That roasty flavor might be at home in a different style beer, but even in a Black IPA it's probably lending a bit too much burnt roast character to the malt. I suppose that the acidulated might offset the raised PH of a lot of roast, but even in beers with much more dark malt, it's unusual to see anything more than an ounce or two for mash PH adjustment.
Just looking at the recipe, I imagine an incredibly bitter, tart, burnt flavor. You might enjoy it more as a Russian Imperial Stout where you could keep the chocolate, increase the base malt to raise the OG into the1.080 range or better, add some oats and get the bitterness into a friendlier range.
For an IPA, I'd lose the chocolate completely, raise the OG substantially with base malt, adjust the acid malt to lose any tartness and lower the IBUs. Your hop schedule looks sort of awesome with the exception of the monstrous bittering charge. I completely disagree that Magnum isn't useful as a flavor and aroma hop. It can lend a wonderful noble dank quality with orange/citrus/floral/spice notes when used as a late hop and dry hopping. One of my all-time favorite IPAs uses just Columbus and Magnum, all in late boil and whirlpool. I'd leave your hops pretty much the same but move most of the Magnum into the late hops and use just enough at 60 to get your overall IBUs into the 100 to 120 range.
Good luck!
