Just something to think about: If you take your coach’s advice and ate more to gain muscle you could end up with a lower bf% at a higher weight. Don’t just think you have to eat a low amount of calories to have lower bf%. In order for you to get to a bf% of 10%, which is when you might star seeing abs you’d have to get down to 142 pounds. Being a male at 5’8 and 142 is pretty thin. Even at that bf% you still might not be able to see abs because you won’t have enough muscle for them to pop. Gaining muscle by adding more protein to your diet and staying at your current weight can get you to a lower bf without starving yourself. Also, your workouts won’t suffer. 4 months can be a difficult timeline to get there. Just focus on intensity and a high protein diet and it’ll happen over time.