The point of lifting weights under the BFL system is to work the muscles until failure. As long as you're doing that, you're going to be stimulating muscle growth. It doesn't matter if the weights aren't going up, as long as you're struggling to lift those last few reps, you're stimulating your muscles. Keep trying with the 35s, even if you can only do 3 reps before failure. Eventually you'll get to 4, then to 5 and 6, then you'll be ready to increase the weight.
Remember, muscle growth is the goal here, not necessarily increasing weights.
© Abbott Laboratories,2013