Question : Pantone color changes back to previously choosen color

I am creating a file for print that features an image (photograph) over a radial gradient. There is one word of text. I am somewhat familiar with preparing CMYK files for print, but I am learning a whole new game with PMS colors. A previous question posted here described exactly what I am experiencing, only the answer wasn't quite what I was looking for (the asker was screen printing. We will be doing a 4 color process print)

Basically, my problem: I was told by our printers this needs to be a CMYK file, with Pantone colors called out.  I selected a color from my Pantone coated color bridge set that would suit the text. Later on I found a better color for the text and changed it to that PMS color. I went back to double check it had saved the change, and instead it was a different color, though very close the first color I chose. Frusterated, I tried doing a color overlay with the new color I wanted and it saved fine.

The previous answerer suggested creating the file in multichannel mode, which is not something I am comfortable with given that these files will ultimately be shared with others who are also not familiar with this file mode. (And the photograph is from a CMYK file...not sure how that affects things)

Also, I don't know how reliable a layer style (for the color overlay) will be when printing? I could stamp the layer to flatten the effects, but then the text will not be editable for the others.

Is there a way to keep this in CMYK mode and get the text to the Pantone color I want? (Note: this new color did not have any gamut warnings)

Please help!

Thanks
Cderosier

Answer : Pantone color changes back to previously choosen color

Yes, yes and yes.

(And to be clear, when I 'double checked' these colors it is from the info palette that I did that.)

More specifically:
I started with PMS 7490c.
Reopened the file later and changed it to 377c.
After hitting "ok" button in info palette, (then check mark to finalize text), I rehighlight the text ---> go into the color picker ---> select custom...and the color selected is now 576c.

My document color mode is CMYK.

I understand Photoshop might be compensating...so my question now is what document mode allows me to chose 377c?

What would happen if I keep it in CMYK and use a color overlay to get 377c? (Since it allows me to do that).

Thanks so much
cderosier