“Never” is an awfully rigid term, but you must be extremely careful in changing the project’s goals, which this is.
I always asked myself “How can I improve the project if I spent 5% more effort?” That had a major impact on many of my projects from my second one out of college to my last job before retirement.
However, I generally did a lot more with less code than my colleagues.
Also, I did not add features upon request by others unless it was critical to the project’s goal. My first project ran 18 years without a single update and increased the company’s share of the market by 20%.
If you add too much extra code, you may not finish. After all, nothing counts until the project is implemented.