EPY vs. EPR

First I thought that this is the same film, only in two different color balances, but
as far as I know EPY is a newer film, from around '89, while EPR has been
in this edition from around mid 70's, and has existed even in 60's (used on moon)

I haven't used EPR yet, just ordered 8 rolls of it to try it out.
So has anyone here compared it on the same subjects and lighting?
Is EPY just a modified EPR?

It is more likely that EPY is modified EPN or some other faster chrome. I could be all wet, but it seems to me that making a film T balanced causes some speed loss. I know NPL has larger grain (at least when viewed on enlargement) than NPS -- both 160 films -- and that portra 100T is comparable (if maybe slightly more grainy) to 160nc -- having box speeds of 100 and 160 respectively.

In that case, EPY could be modified "100 plus" or similar film

Can someone comment on the way EPR looks? Any EPR users? How would you describe it?