Muscle Mass / Body Fat levels while maintaining current weight

[mickc1965]

I understand the science to lower body fat you reduce calories or to increase muscle mass you have surplus calories but if calorific intake was neutral to maintain body weight at 180lbs with protein intake at 220g and following the standard HST routine (2 weeks at 15s, 2 weeks at 10s, 2 weeks at 5s followed by a further two weeks on 5s then SD) am I likely to stand still or can muscle mass increase while lowering body fat?