While I do agree with this, it's pretty much all what PDs have to judge IMGs, or AMGs from mid-tier programs. Otherwise, we'd be looking at a world where the ivy league guys get matched first, then mid-tier schools etc...
The simple fact is...the test works. The statisticians behind it know how to make scores comparable. Somewhere on the NBME site it says the step scores obtained within 2 to 3 years of each other are comparable (fair enough, more than 3 years and chances are the test has changed quite a bit) so I wouldn't worry about it being comparable to the guys doing it before the changes set in.
If you really want to be sure that these changes aren't going to affect your score, dig up the stats for the past 6-5 years and look at the means and SD. I reckon they'd be close to each other, maybe an increase in the mean?
I don't think that they're gonna hold a nation-wide meeting titled "how to evaluate the new step scores" I think what's going to happen is that the number of people scoring 260+ will decrease, prompting PD to start looking at more applicants with above average to average scores.
On a completely unrelated note
During high school I was at a british school. Long story short, you've got 3 sets of exams to go through in years 10,11,12. They changed every single curriculum the year that I did each exam. The year that I graduated high school, almost all unis in australia decided to abandon undergrad medicine (MBBS) and switched to postgrad MD. Fast forward to med school....I was thinking about applying to england for residency, BUT GUESS WHAT? the year that I graduate med school, england is changing their exam from the current PLAB to what they're gonna call the UKNLE (UK national licensing exam). PLAB is piss easy, UKNLE is going to be similar to USMLE. So doing residency in the UK is going to become more challenging.
Just my luck eh?
Don't make excuses, work hard, and you'll make it!