To answer your question directly: you could either cut the amount of bittering hops added at T-60 minutes (try dropping 1/3 to start with, especially in an IPA), or add it later in the boil (try adding the full amount at T-40 minutes).
Now, as a bit of explanation, I'm making an assumption here, so forgive me if I'm wrong. I'm thinking you're just starting out and haven't got a deep grasp of what your ingredients are doing for the brew. Hops come in all sorts of different flavors and types, but a hop pellet of any one type can be used for aroma, flavor or bittering, depending almost entirely on the amount of time it's in the boil (or even after the boil, as in "dry hopping"). Some hops are better for certain characteristics than others, though (Magnum is a great bittering hop, and Cascade is excellent for flavor and aroma, as well as dry hopping).
If you were to get a kit for an IPA which had only one type of hops in the kit, the instructions would tell you when to add that hop in order to get different characteristics. As a basic example, take an ounce of East Kent Goldings. Starting from the time the wort hits boil temps, generally that's considered the 60-minute mark (T-60, or the total amount of time you will boil the wort until "flameout" and cooling), you can add hops to get bittering characteristics. If you were to taste the wort after five minutes of boiling the hops, you wouldn't taste much hop flavor at all, and no bitterness, but you'd really smell it. A few more minutes and you can start tasting it more, but still no real bitterness. After twenty minutes, you'd not smell it much, but the taste would still be there, and the hint of bitterness would start to creep in.
After forty minutes, the hops doesn't taste like much, you can't really smell it, but that bitterness is increasing rapidly, and from here until the 60-minute boil mark, it's going to get more bitter.
Many British beers and some Belgiums have only a bit of hops thrown in at the beginning of the boil, and often don't have any other hops added at all. These beers are all about the grains, so all the brewers want is some bitterness to balance the sweetness.
Adding hops is all about balance with the grain bill (your malt extracts or grains). Your BB recipe was supposed to be created with this in mind. That being said, though, your tastes are not the same as mine.
That's what makes homebrewing so great: the level of control and experimentation is completely up to the brewer. Brewer's Best simply gives you the ingredients and a suggested recipe. There's no rule saying you have to follow that recipe to a fault.
Good luck on your next batch, and enjoy the hobby!
