I brewed an IPA intended to blow my hop socks off and missed my target OG by 20 points.

DEETS: Built this recipe in BeerSmith with an intended OG of 1.070 and IBU projected at 156. I pitched a 1000 ml starter of 001 right at the peak of action and my 4+ gallons are fermenting to the point my fermentation chamber cant stop it from climbing above 71, I like to ferment my IPA at 64 and havent had a problem keeping it close to that in the past.

QUESTION: It's been 3 days and the temp looks like it has peaked, if I brew a one gallon batch and top it off at this point will the yeast still be able to clean up the warm fermentation flavors? Is there something else I should be concerned about when trying this? has anyone had experience with this