One of the main benefits of using Pantone colors is that you can use colors that simply don't exist with a standard CMYK process.
You say the values don't seem accurate but remember what you see on your screen and what will print is rarely going to be the same. Take in to account calibration issues, different color profiles, differences in paper and things can quickly look "off". Start with the values Pantone give you, run a test print and adjust if you need to.
Pantone is a company purely focused on color matching. They spend a lot of time and resources on making their colors and conversions as accurate as possible. The CMYK values Pantone supply are probably the best you are going to get without doing test prints for your specific case. And keep in mind that theres a high chance you'll never get the color you want.
All of that being said, if it looks "off", try bumping up the Magenta 5-10%, but that is nothing more than guess-work and speculation since I have no idea what your output looks like