I have smoked at least one dozen boxes of PE since 2012 when I was introduced to this cigar, while in Cuba. It is true that is probably one the cigars with the best price/quality ratio but keep in mind the following:
PE has a length of 140 and a ring gauge of 40. Similar dimensions cigars are H. Upmann Majestic, Partagas Deluxe Tubos, Partagas Super Partagas, Romeo Y Julietta No. 1 and maybe a few more. For such brands, under the $150 per box of 25, branding is not decided at the time of rolling but rather at the time of packaging, and is based on plenty of factors. Keep in mind also that Hoyos and Partagas are produced mostly at the same factory.
So one day it might be Palmas Extra, the next Partagas Super. What really differentiates Palmas is the wrapper color, that is darker than Partagas Super and a slight blend difference. But if the demand for Palmas is in one week lets say 100 boxes but the boxes with the dark wrappers are only 90 then some Partagas boxes will be branded Palmas.
The best thing to do is when you buy them in a store is to open the box and check it. Other thing is when you find a batch you like buy as many boxes of that batch as possible. If you buy online then things are not easy, just request the darker wrapper possible.
Still not easy. I will give you a recent example. One of the best Palmas tasted the last four years are boxes coded MUL FEB15. Last week I came across, in LCDH store a box coded MUL MAY15, so I bought it without checking. This box is right now unsmokable, not only a very light non oily wrapper, full of green dots but also taste full of ammonia.