LoopCoder-v2, a parallel loop Transformer model, achieves superior code generation and reasoning performance with two loops, improving SWE-bench Verified from 43.0 to 64.4 points and Multi-SWE from 14.0 to 31.0 points. Variants with three or more loops perform worse, indicating a non-monotonic loop-count effect due to growing positional mismatch and diminishing returns.