People worry a LOT about losing muscle, needlessly. If you have a good training plan and consume quality carbs around your training window, you're not going to lose muscle, you won't. People look smaller than they think they are after losing considerable amounts of fat because there's always more fat to lose than people realize, and extra water, etc. Additionally, there can be fat UNDER the muscle, like in the mid section.
I remember John Meadows (I'm pretty sure it was JM) once wrote in an article that a lot of bodybuilders are surprised how much smaller their arms look once they get close to the show. Is it because they lose muscle? No, there's just always more fat than people think. So, even if you already have some definition, there's still a lot of fat to lose. Unless you're laying in bed for weeks or not training at all, you're not going to lose muscle. You may not GAIN considerable LBM, but you're certainly not going to lose anything.
It sounds like you're on the right track. If you want to get there a little quicker, try cutting carbs a little more significantly on non-training days, like doing veggie carbs only on non training days, no starches. Be sure to compensate with a little extra protein and higher fat macros on that day. Maybe throw in one low calorie day per week? I like to do that on Sunday, no training and I sip on MAG-10 and Metabolic Drive shakes all day. This adds another few pounds a month of pure fat loss.
Once you get down to 10% or whatever you're going for, it'll be easier to add more carbs back in and maintain. But, to get down there you'll have to cut more carbs, I recommend cutting them on non training days so you can ensure you get the most out of your sessions.