YES

1 decompositions
 #1 -----------
   1: a(a(b(b(x1)))) -> b(b(b(b(b(a(a(a(a(a(x1))))))))))

@Development Closedness
--- R
   1: a(a(b(b(x1)))) -> b(b(b(b(b(a(a(a(a(a(x1))))))))))

--- S
   1: a(a(b(b(x1)))) -> b(b(b(b(b(a(a(a(a(a(x1))))))))))