LoopCoder-v2, a parallel loop Transformer model, achieves significant gains in code generation and reasoning 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, showing diminishing returns and oscillatory updates due to positional mismatches from cross-loop offsets.