Suppose that, we have some real numbers $r_1,r_2,\dots,r_m \in [0,1]$; and we study a sum,
$$
S_1= \sum_{i=1}^m \binom{m}{i}(-1)^{i-1}f(r_i),
$$
for $f:[0,1]\to[0,1]$ a concave bijection. Now, take another sequence $z_1,\dots,z_n\in [0,1]$ with $r_i\geq z_i$ for $i=1,2,\dots,m$. 

Can we prove or disprove,
$$
S_1 = \sum_{i=1}^m \binom{m}{i}(-1)^{i-1}f(r_i) \geq S_2 = \sum_{i=1}^m \binom{m}{i}(-1)^{i-1}f(z_i)?
$$
In case, does it depend on the very function $f(\cdot)$ (for instance, can we say something, for $f(x)=x(2-x)$). 

I tried to pull some results from majorization; but the presence of annoying signs makes it somehow untouchable. Any help is appreciated!