EPQ Vs. PPQ Impact On Value Of Star Note?

Timewise, the 'Q' designations probably increase the price.
From PMG Grading Standards:
"An Exceptional Paper Quality (EPQ) note is, in the opinion of PMG graders, completely original. EPQ notes will not have been physically, chemically, or materially processed to give the appearance of a higher grade. Notes exhibiting normal wear-and-tear for their grade are eligible. All notes graded Very Fine 25 and higher will be evaluated for the EPQ designation. Notes must qualify for the EPQ designation to grade Gem Uncirculated 65 and higher."

From PCGS Grading Standards:
To distinguish notes that bear all the hallmarks of complete originality and outstanding paper quality for the grade, we will affix a "PPQ" (Premium Paper Quality) designation to the grade (e.g.: "Gem New 65PPQ"). These are notes that bear no visible evidence of restoration and that retain all signs of fully original paper quality, such as paper wave, embossing, and bold ink color and eye appeal. "PPQ" notes should also have above average paper for the grade that is free of defects such as tears, pinholes, or other problems. This is not done to penalize those notes that are not fully original, as many are very collectible and highly valuable. Instead, this system is designed to reward those notes, both circulated and New, that possess premium paper quality and complete originality. It should be understood that even though a note may be fully original and free of any restoration, it still might not qualify for the "PPQ" designation."

I agree with Tech and lettow, and will add, typically advanced collectors will gravitate towards collectible paper currency that has a EPQ/PPQ designation. Original paper qualities notations usually weed out problem notes. The TPG's have gotten pretty good at detecting washed, pressed, trimmed and repaired notes. They may not catch them all, after all they're human.

CGA uses OPQ (original paper quality) and Superior uses SPQ (superior paper quality). All of these designations imply original paper.

Ain't that the truth frog.

Those middle grades are sometimes a coin toss. We have all seen 64's that maybe should have been 65's, and 65's that easily could have been 66's. The higher (Super GEM) notes tend to hold their own. Most 67 and up notes are truly spectacular, especially the large size, iconic notes.