YES

   1: +(x1,0()) -> x1
   2: +(x1,s(x2)) -> s(+(x1,x2))
   3: +(0(),x2) -> x2
   4: +(s(x1),x2) -> s(+(x1,x2))
   5: inc(x1) -> s(x1)
   6: +(x1,x2) -> +(x2,x1)
   7: inc(+(x1,x2)) -> +(inc(x1),x2)

@Rule Labeling
--- R
   1: +(x1,0()) -> x1
   2: +(x1,s(x2)) -> s(+(x1,x2))
   3: +(0(),x2) -> x2
   4: +(s(x1),x2) -> s(+(x1,x2))
   5: inc(x1) -> s(x1)
   6: +(x1,x2) -> +(x2,x1)
   7: inc(+(x1,x2)) -> +(inc(x1),x2)

--- S
   1: +(x1,0()) -> x1
   2: +(x1,s(x2)) -> s(+(x1,x2))
   3: +(0(),x2) -> x2
   4: +(s(x1),x2) -> s(+(x1,x2))
   5: inc(x1) -> s(x1)
   6: +(x1,x2) -> +(x2,x1)
   7: inc(+(x1,x2)) -> +(inc(x1),x2)