cant get rid of tint!!

So, I am working on a document created by someone else. I've selected a line and changed the colour to a spot colour in the swatches. But I can see that although it has changed the colour it's only a tint of that colour.

I've selected the 'colour' window and have moved the slider to change the tint, but I still can't get it to 100%. I have tried changing the line to different colours, it does change but the amount of tint stays the same.

In Indesign, which I usually use, if you click on an object it will tell you what percentage of the colour it is, so that you can change it, but I can't see anything like that in Illustrator. Although the tint slider does appear on the 'colour' window, it doesn't say what tint it currently is, or even indicate that it is a tint, except that it obviously is because it's lighter.

I've looked to see if it has a style applied to it, but it doesn't seem to.

I'm sure I've had this problem before and solved it, but I can't for the life of me work it out.

I would be so thankful if someone could help.

P.S. I have spent time googling this issue and looking it up in this forum but couldn't find an answer. Apologies if this has been answered many times before.