Ravenloft: THW - Dark Gift Saves - Do you still add your Proficiency Bonus if you are NOT proficient in the save?

On the new Ravenloft, the Horrors Within, in the Ch 1 Dark Gift feats section, each feat (vice Touch of Death) has a save associated with rolling a nat 1 on a d20 test, but the wording is unclear.

"Make a [Constitution / Wisdom / Charisma] saving throw (DC 13 plus your Proficiency Bonus)."

Is the intent to add your proficiency bonus to the DC, and if so, do you still add it if the person is not proficient in that save?

Yes. The way it's written, the Proficiency Bonus is added to the saving throw's DC that you're rolling against. So the DC is 15 at level 1, 16 at level 5, 17 at level 9, 18 at level 10, and 19 at level 11. All the way up to 20 if you use the Ioun Stone that increases your PB by 1.

Whether you're proficient in the save or not is irrelevant.