An engineer is designing a component for a sequence-processing model. They are considering two approaches for incorporating information about the relative positions of elements in a sequence.

Approach A: A positional bias is added to the attention scores before the main attention calculation is completed.

Approach B: A positional bias is added before the self-attention operation, and a second, distinct positional bias is added after the self-attention operation has concluded, effectively 'sandwiching' the core mechanism.

Analyze the potential rationale behind Approach B. Why might adding a positional bias both before and after the self-attention operation be more effective for preserving positional information across multiple layers of the model compared to adding it only before?