Although ~1500kcal is quite a lot on a day to day basis, it doesn't compare to the deficit you've already created running RFL. So, technically, it's just a small margin on your overall fat-loss plan.
My suggestion would be to just follow the diet-break as it is outlined, because it is there for a reason. Just try to stick to maintenance kcal and don't go overboard. After your diet-break you can evaluate and optionally diet some more.
I just don't want to gain fat.
As a final note, don't stress yourself if you messed up one time. Because fat-loss is a long/slow progress, you won't instantly become fat or lean (exceptional eaters aside). Sit back and enjoy the ride.