$R$ a ring $(1\neq 0)$, $\mathbf{Perf}(R)$ is the category of perfect complexes (of right $R$-modules).

Suppose that $A_{\bullet}\rightarrow B_{\bullet}\rightarrow B_{\bullet}/A_{\bullet}$ a short exact sequence in $\mathbf{Perf}(R)$ such that

- $A_{\bullet}\rightarrow B_{\bullet}$ is a cofibration in the projective model structure of chain complexes $\mathbf{Ch}_{R}$.
- The homology of the chain complexes $A_{\bullet}$, $B_{\bullet}$ and $B_{\bullet}/A_{\bullet}$ is concentrated at level $n$ (the same $n$ for all $A_{\bullet}$, $B_{\bullet}$ and $B_{\bullet}/A_{\bullet}$ complexes).

Here is my question: Is it true that $A_{\bullet}\oplus B_{\bullet}/A_{\bullet} $ is isomorphic to $B_{\bullet}$ in homotopy category $Ho(\mathbf{Ch}_{R})$.