Not necessarily.
I have seen xhigh go down several rabbit holes, dwell on edge cases and write worse code as a result; it literally distracted itself into writing a complex chain of functions ignoring my prompt, when on “low” reasoning it gets it right on a prompt that requires a few lines of code in the right places.
Simon Willison’s blog has another example (SVG of a circle).
It’s a bit like how giving LLMs access to web search tools can cause them to go down a blind alley based on their first “reasoning” output that then leaves them unable to solve a puzzle correctly that they can fully solve on their own.