Forget about CR and slope. They're not talking about ratings and differentials here. What they are saying (I think - correct me if I'm wrong, guys) is that it could very well help you over the mental block of the number 85 when you give yourself an "excuse" to shoot it.
We all have a comfort zone and it's easy to get out if it in both directions. If I'm playing super well and am ready to turn in an all time score, I'm very aware of it and it's hard to avoid the thinking that a reversion to the mean before the 18 holes is up is inevitable.
If you play shorter tees then you can expect to shoot lower scores, and then get used to shooting lower scores (even if those lower scores provide for higher differentials), and then when you move back you aren't as afraid to get over that hump because you've already done it (at least sort of) several times before.
Hope that makes sense.
This didn't work for me the other night, but I can't hit the broad side of a bard these days.