If you find that you're doing less reps than the previous workout for bench try doing a deload week. So drop the weight by 10% and start again from there. You might start off doing 4 sets of 8 reps, then the next work out go for 4 sets of 10 reps. Once you reach 4 sets of 12 reps you can up the weight again. This is known as progressive overload.
5 times per week is too much really and you will be able to hit your goal simply by training bench twice week, this will allow recovery.
Don't forget to train the rest of the muscles, any muscular imbalances can lead to injuries and exercises such as overhead press, dumbbell bench and any other pressing exercises will assist you with training the muscles required to reach your goal.